Null value Check in DataTable?

TheMSsForum.com: The Microsoft Software Forum

The MSS Forum ‹ Ado
- Archive
  - Biz
  - MCSE
  - CRM
  - Drivers
  - Framework
  - ADO
  - ASP
  - Compact
  - Forms
  - Dotnet
  - C#
  - VB
  - FontpageGen
  - Excel
  - WorkSheet
  - Exchange
  - Setup
  - Fox
  - Fontpage
  - ASP
  - IIS
  - Entourage
  - Money
  - Messanger
  - PocketPC
  - Powerpoint
  - Project
  - Publisher
  - Excel
  - VB
  - Security
  - Portal
  - Services
  - SQLServerDev
  - SVCS
  - SQLServer
  - VB
  - VC
  - MFC
  - ExcelGen

- Previous
  - 1
    - DataAdapter.Update() returns error. Hi, I am populating a dataset from a stored procedure, which returns multiple resultsets. One of the resultset is formed with a join condition from two tables. I am updating the fields of the respective datatable. Then update the first table in the database using DataAdapter.Update(). This succeeds. Subsequently, I update the fields of the second table in the datatable and update the respective(second) table in the database using DataAdapter.Update(). This throws the error, "Concurrency violation: the UpdateCommand affected 0 of the expected 1 records.". Dataset.HasChanges() returns true before each update. I give below the code. // First Table DataRow dr = dtOrderInfo.Rows[iSelectedRow]; dr.BeginEdit(); // Data Row changes. ... ... dr.EndEdit(); // connect to database and execute as follows. cnDatabaseOpen(strdbconnect); SqlDataAdapter da = new SqlDataAdapter("Select top 0 * from OrderDetail", cnDatabase); SqlCommandBuilder scb = new SqlCommandBuilder(da); da.Update(dtOrderInfo); da.Dispose(); cnDatabaseClose(); // Second Table dr = null; dr = dtOrderInfo.Rows[iSelectedRow]; dr.BeginEdit(); // Data Row changes. ... ... dr.EndEdit(); // connect to database and execute as follows. cnDatabaseOpen(strdbconnect); SqlDataAdapter da = new SqlDataAdapter("Select top 0 * from Orders", cnDatabase); SqlCommandBuilder scb = new SqlCommandBuilder(da); // Following line throws error. da.Update(dtOrderInfo); da.Dispose(); cnDatabaseClose(); I get the error in da.Update() for the second table. Any help would be greatly appreciated. Thanks Manohar Tag: Null value Check in DataTable? Tag: 140639
  - 2
    - Unexplained entry in Oledb Excel schema table Hi I have an excel workbook with 4 worksheets. When I connect to this workbook using an Oledb connection, I use GetOleDbTableSchema to retrieve the names of the worksheets ("TABLE_NAME"), only the schema table returns 5 rows, not 4. If my worksheet names are Sheet1, Sheet2, Sheet3 and Sheet4, I would expect to get 4 rows in the schema datatable, with "TABLE_NAME" as Sheet1$, Sheet2$, Sheet3$ and Sheet4$, however, I get those four, and an extra one, say Sheet1$_ Has anyone come across this before who could offer either an explanation, or a solution, or preferably both? Thanks in advance for your help. Tag: Null value Check in DataTable? Tag: 140632
  - 3
    - How to get the primary key Hello there, I want to write a function returning the primary key name of a certain table. The following function successfully returns the names of all fields of a table: public string[] GetFieldNames(string tableName) { string[] fieldNames = null; IDbConnection conn = _factory.CreateConnection(true); try { string[] restrictions = { null, tableName, null }; DataTable dataTable = (conn as DbConnection).GetSchema("Columns", restrictions); if (dataTable != null) { fieldNames = new string[dataTable.Rows.Count]; for (int i = 0; i < dataTable.Rows.Count; i++) fieldNames[i] = dataTable.Rows[i] ["COLUMN_NAME"].ToString(); } return fieldNames; } finally { conn.Close(); } } An interesting part in the upper function is, that the table name is at the second position in the restrictions array instead on the third, as I have seen several times in samples found in the internet. In my case I get the field names with the table name at the second position in the array. Now I wrote a function to get the primary key of a table: public string GetPrimaryKeyName(string tableName) { IDbConnection conn = _factory.CreateConnection(true); try { string[] restrictions = { null, tableName, tableName }; DataTable dataTable = (conn as DbConnection).GetSchema("PrimaryKeys", restrictions); if (dataTable != null) { if (dataTable.Rows.Count > 0) return dataTable.Rows[0] ["COLUMN_NAME"].ToString(); } return null; } finally { conn.Close(); } } That function never returns me the primary key, regardless on which position the table name is in the restrictions array. I heard that the upper function does not work for connections based on Oracle. Is that true? Regards, Norbert Tag: Null value Check in DataTable? Tag: 140630
  - 4
    - How to get the last created or modified dataset Hello, is there a possibility to get the ID of the last created or modified dataset of a table via ADO.NET? Is there a database independent way? In SQL Server you can call the scope_identity() function, but this won't work in Oracle, MySQL, Access a.s.o. Thanks in advance, Norbert Tag: Null value Check in DataTable? Tag: 140628
  - 5
    - TransactionScope promotion & isolation levels Our project is using the System.Transactions.TransactionScope class to provide an ambient transaction which our DAL classes can leverage. I'm looking for some information about the TransactionScope class to answer a few questions about how it behaves when a transaction is promoted to a distributed transaction. Our environment is ASP.NETv2 on Win2003 calling db server running SQL2005. In pseudo-code, we do something like this: Using (scope1 = New TransactionScope()) DalA.IssueInsertAndUpdateStatementsToDb1() Using (scope2 = New TransactionScope(TransactionScopeOptions.Suppress)) DalB.IssueInsertToDb2() scope2.Complete() End Using scope1.Complete() End Using The first TransactionScope is used to create a transaction for a series of DAL inserts and updates to our primary database. Then we start a second, nested scope with the transaction option set to "Suppress" and it is used to insert a record into a second database (on the same db server). Both databases are configured for a default isolation level of ReadCommitted, but we are seeing some transactions come across at the Serializable isolation level. My question is: is the Serializable isolation level being caused by the use of TransactionScope (and its implicit use of DTC)? If we were to provide the appropriate TransactionOption class to the constructor of each scope object, would it provide us with ReadCommitted isolation level, or does the use of DTC always force the use of Serializable? Thanks, Chris Tag: Null value Check in DataTable? Tag: 140627
  - 6
    - DataReader values and .ToString Hello, In order to avoid errors, I have all my DataReader-fields converted with a .ToString. This in case some record could have Null-fields and an error would be thrown. This works fine, except for "money" fields in SQL-Server. When I enter e.g. ? 2,50 and I read it back with a DataReader without .ToString, I get the correct display. However using .ToString, I get no valuta-sign and the value is multiplied by 10 000. When trying to StringFormat the DataReader.ToString, I get a syntax error. Can someone explain this to me an offer some help? Many thanks and greetings, Michel Tag: Null value Check in DataTable? Tag: 140619
  - 7
    - SqlDependency.Start KeyNotFoundException - Possible Bug I'm working heavily with query notifications in SQL Server 2005 and I'm now getting the following exception: System.Collections.Generic.KeyNotFoundException: The given key was not present in the dictionary. This was working for quite a while and then it stopped. At first, the exception was intermittent, but now it's permanent. The exception is happening deep inside of a System.Data.dll in a class called SqlDependencyProcessDispatcher in a method defined as follows: private bool Start(string connectionString, out string server, out DbConnectionPoolIdentity identity, out string user, out string database, ref string queueService, string appDomainKey, SqlDependencyPerAppDomainDispatcher dispatcher, out bool errorOccurred, out bool appDomainStart, bool useDefaults) It looks like the method is checking a dictionary for particular key; then, if it's found, it retrieves the item from the dictionary. Looking at Reflector it appears that this lookup may not be threadsafe. It has a few code blocks inside structured like this: if (!this._sqlDependencyPerAppDomainDispatchers.ContainsKey(appDomainKey)) { lock (this._sqlDependencyPerAppDomainDispatchers) { this._sqlDependencyPerAppDomainDispatchers[appDomainKey] = dispatcher; } } These should probably be using sqlDependencyPerAppDomainDispatchers.TryGetValue instead or should move the lock to the outside of the if statement. No one on the Internet seems to have ever encountered this. Two partial stack traces appear below. They're partial in that I've ommitted a long set of calls from our interal app framework that are orthogonal to the problem. The NT user making these calls is a local administrator on the database server. The calls work a lot of the time, but break and seemingly random moments. We use a preconfigured SQL Server Service Broker Queue named QueryChangeMessages and a service called QueryChangeNotifications. Please help. One stack trace looks like this: [KeyNotFoundException: The given key was not present in the dictionary.] SqlDependencyProcessDispatcher.Start(String connectionString, String queue, String appDomainKey, SqlDependencyPerAppDomainDispatcher dispatcher) +0 System.Data.SqlClient.SqlDependency.Start(String connectionString, String queue, Boolean useDefaults) +672 System.Data.SqlClient.SqlDependency.Start(String connectionString, String queue) +7 Nvidia.PolicyInjection.CallHandlers.SqlDependencyConnection.StartInternal() +103 [DataException: An error occurred while calling ConfigurationManagement.Start for connection string named ConfigurationManagement on SQL Server Service Broker Queue QueryNotificationQueue.] ... Another stack trace looks like this: Server stack trace: at System.ThrowHelper.ThrowKeyNotFoundException() at System.Collections.Generic.Dictionary`2.get_Item(TKey key) at SqlDependencyProcessDispatcher.SqlConnectionContainer.ProcessNotificationResults(SqlDataReader reader) at SqlDependencyProcessDispatcher.SqlConnectionContainer.SynchronouslyQueryServiceBrokerQueue() at SqlDependencyProcessDispatcher.SqlConnectionContainer..ctor(SqlConnectionContainerHashHelper hashHelper, String appDomainKey, Boolean useDefaults) at SqlDependencyProcessDispatcher.Start(String connectionString, String& server, DbConnectionPoolIdentity& identity, String& user, String& database, String& queueService, String appDomainKey, SqlDependencyPerAppDomainDispatcher dispatcher, Boolean& errorOccurred, Boolean& appDomainStart, Boolean useDefaults) at SqlDependencyProcessDispatcher.Start(String connectionString, String queue, String appDomainKey, SqlDependencyPerAppDomainDispatcher dispatcher) at System.Runtime.Remoting.Messaging.StackBuilderSink._PrivateProcessMessage(IntPtr md, Object[] args, Object server, Int32 methodPtr, Boolean fExecuteInContext, Object[]& outArgs) at System.Runtime.Remoting.Messaging.StackBuilderSink.PrivateProcessMessage(RuntimeMethodHandle md, Object[] args, Object server, Int32 methodPtr, Boolean fExecuteInContext, Object[]& outArgs) at System.Runtime.Remoting.Messaging.StackBuilderSink.SyncProcessMessage(IMessage msg, Int32 methodPtr, Boolean fExecuteInContext) Exception rethrown at [0]: at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg) at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type) at SqlDependencyProcessDispatcher.Start(String connectionString, String queue, String appDomainKey, SqlDependencyPerAppDomainDispatcher dispatcher) at System.Data.SqlClient.SqlDependency.Start(String connectionString, String queue, Boolean useDefaults) at System.Data.SqlClient.SqlDependency.Start(String connectionString, String queue) ... Tag: Null value Check in DataTable? Tag: 140613
  - 8
    - SqlDependency.Start - Getting KeyNotFoundException I'm working heavily with query notifications in SQL Server 2005 and I get the following exception: System.Collections.Generic.KeyNotFoundException: The given key was not present in the dictionary. This was working and then it stopped. At first, the exception was intermittent, but now it's permanent. The exception is happening deep inside of a System.Data.dll in a class called SqlDependencyProcessDispatcher in a method defined as follows: private bool Start(string connectionString, out string server, out DbConnectionPoolIdentity identity, out string user, out string database, ref string queueService, string appDomainKey, SqlDependencyPerAppDomainDispatcher dispatcher, out bool errorOccurred, out bool appDomainStart, bool useDefaults) It looks like the method is checking a dictionary for particular key; then, if it's found, it retrieves the item from the dictionary. Looking at Reflector it appears that this lookup may not be threadsafe. It has a few code blocks inside structured like this: if (! this._sqlDependencyPerAppDomainDispatchers.ContainsKey(appDomainKey)) { lock (this._sqlDependencyPerAppDomainDispatchers) { this._sqlDependencyPerAppDomainDispatchers[appDomainKey] = dispatcher; } } These should probably be using sqlDependencyPerAppDomainDispatchers.TryGetValue instead or should move the lock to the outside of the if statement. No one on the Internet seems to have ever encountered this. Two partial stack traces appear below. They're partial in that I've ommitted a long set of calls from our interal app framework that are orthogonal to the problem. The NT user making these calls is a local administrator on the database server. The calls work a lot of the time, but break and seemingly random moments. We use a preconfigured SQL Server Service Broker Queue named QueryChangeMessages and a service called QueryChangeNotifications. Please help. One stack trace looks like this: [KeyNotFoundException: The given key was not present in the dictionary.] SqlDependencyProcessDispatcher.Start(String connectionString, String queue, String appDomainKey, SqlDependencyPerAppDomainDispatcher dispatcher) +0 System.Data.SqlClient.SqlDependency.Start(String connectionString, String queue, Boolean useDefaults) +672 System.Data.SqlClient.SqlDependency.Start(String connectionString, String queue) +7 Nvidia.PolicyInjection.CallHandlers.SqlDependencyConnection.StartInternal() +103 [DataException: An error occurred while calling ConfigurationManagement.Start for connection string named ConfigurationManagement on SQL Server Service Broker Queue QueryNotificationQueue.] ... Another stack trace looks like this: Server stack trace: at System.ThrowHelper.ThrowKeyNotFoundException() at System.Collections.Generic.Dictionary`2.get_Item(TKey key) at SqlDependencyProcessDispatcher.SqlConnectionContainer.ProcessNotificationResults(SqlDataReader reader) at SqlDependencyProcessDispatcher.SqlConnectionContainer.SynchronouslyQueryServiceBrokerQueue() at SqlDependencyProcessDispatcher.SqlConnectionContainer..ctor(SqlConnectionContainerHashHelper hashHelper, String appDomainKey, Boolean useDefaults) at SqlDependencyProcessDispatcher.Start(String connectionString, String& server, DbConnectionPoolIdentity& identity, String& user, String& database, String& queueService, String appDomainKey, SqlDependencyPerAppDomainDispatcher dispatcher, Boolean& errorOccurred, Boolean& appDomainStart, Boolean useDefaults) at SqlDependencyProcessDispatcher.Start(String connectionString, String queue, String appDomainKey, SqlDependencyPerAppDomainDispatcher dispatcher) at System.Runtime.Remoting.Messaging.StackBuilderSink._PrivateProcessMessage(IntPtr md, Object[] args, Object server, Int32 methodPtr, Boolean fExecuteInContext, Object[]& outArgs) at System.Runtime.Remoting.Messaging.StackBuilderSink.PrivateProcessMessage(RuntimeMethodHandle md, Object[] args, Object server, Int32 methodPtr, Boolean fExecuteInContext, Object[]& outArgs) at System.Runtime.Remoting.Messaging.StackBuilderSink.SyncProcessMessage(IMessage msg, Int32 methodPtr, Boolean fExecuteInContext) Exception rethrown at [0]: at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg) at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type) at SqlDependencyProcessDispatcher.Start(String connectionString, String queue, String appDomainKey, SqlDependencyPerAppDomainDispatcher dispatcher) at System.Data.SqlClient.SqlDependency.Start(String connectionString, String queue, Boolean useDefaults) at System.Data.SqlClient.SqlDependency.Start(String connectionString, String queue) ... Tag: Null value Check in DataTable? Tag: 140612
  - 9
    - GridView databinding I have a GridView which is bound to a table. The user has the ability to change some defaults and then run a process from this. This all worked fine until I added in an auto postback to one of the controls to tie in some other functionality. After the post back, and at the end of page load complete, everything is as it should be, but then the GridView does an automatic databind (after load complete) and wipes it all out. Is there anyway to keep this automatic update from occuring, or cancel it or whatever? Thanks. Tag: Null value Check in DataTable? Tag: 140609
  - 10
    - Database Persistance Hi I'm not sure whether I've given this post the correct title, but I'm a bit unsure of where to put it. I have a database that holds information about several of our users. This database is stored on a central server, with an application that periodically performs some processing, which may or may not update the database. It is possible that some times this data will update several times a minute. Here's my problem - I would like to create an application, in a remote location to the main database server that displays the database contents. This applications would need to update its view of the database as soon as the database changes in order to ensure that only the most up to date information is being displayed. I've previously done this by periodically re-reading the database and updating the fields that have changed on screen, however as I add more terminals, this may cause a problem. So ideally I would like a callback or trigger to be called when the database updates that informs the correct client, so that it can update it's screen accordingly. Is this possible, or am I barking up the wrong tree? Is there a better way of doing it? I'd be very grateful if you could give me your thoughts. I am developing the main client application in C#, and the database is currently MySQL. It would be possible to change the database if this made things easier, however it would have to be a free alternative! Many thanks Steve Tag: Null value Check in DataTable? Tag: 140601
  - 11
    - Detach database from SQL Server Hello, When I have closed my appliciation in VB.NET, and I try to detach my database from SQL SERVER, I often get a message that the database cannot be detachted, because it is still in use. So I think there is some code missing in my application (in the MDI_FormClosing?) to make my database is no longer in use. I already put a Connection.Close in the FormClosing also in a Finally-block of that FormClosing, but that does not seem to be enough. Can someone help me with that? Many thanks and greetings, Michel Tag: Null value Check in DataTable? Tag: 140599
  - 12
    - delete row from dataGridView problem Hi All, I have been failing to delete a row from dataGridView. I use typed dataset. Here is my code, please advice what wrong is here? private void MainForm_Load(object sender, EventArgs e) { // TODO: This line of code loads data into the 'lodgersDataSet1.Table_Lodgers' table. You can move, or remove it, as needed. this.table_LodgersTableAdapter1.Fill(this.lodgersDataSet1.Table_Lodgers); } private void dataGridViewLodgers_RowsRemoved(object sender, DataGridViewRowsRemovedEventArgs e) { string strConnString = @"Data Source=XP\SQLEXPRESS;Initial Catalog=Lodgers;Integrated Security=True"; SqlConnection sqlConnection = new SqlConnection(strConnString); SqlDataAdapter da = new SqlDataAdapter("SELECT * FROM Table_1",sqlConnection); MyDataSet myDataSet = new MyDataSet(); da.Fill(myDataSet, "Table_1"); // myDataSet is updated, row is deleted properly // DataRow dr = myDataSet.Table_1.Rows[e.RowIndex]; myDataSet.Tables["Table_1"].Rows.Remove(dr); // Update returns 0 !!! // int ret = daLodgers.Update(dsLodgers2, dsLodgers2.Tables[0].TableName); myDataSet.Table_1.AcceptChanges(); myDataSet.AcceptChanges(); } Thank you in advance A. Tag: Null value Check in DataTable? Tag: 140596
  - 13
    - ExecuteNonQuery within the loop of a datareader Hello, How can I use an ExecuteNonQuery within the loop of a datareader? My code is as follows: Dim cmdToProcess As New SqlClient.SqlCommand Dim rdToProcess As SqlClient.SqlDataReader With cmdToProcess .CommandText = " SELECT * FROM tblDetails " .Connection = cn End With rdToProcess = cmdToProcess .ExecuteReader Select Case rdToProcess Case True Do 'here I want to add or update data Dim cmdToChange As New SqlClient.SqlCommand With cmdToChange .CommandText = "INSERT INTO tblNew(AD_Action) VALUES (@Action)" .Parameters.AddWithValue("@Action", rdToProcess("DE_Number")) .Connection = cn End With cmdToChange.ExecuteNonQuery Loop until not rdProcess.Read End Select At "cmdNieuweCafetariaActiedetail.ExecuteNonQuery", I get the message that I have to close the first datareader in order to execute, but then my code cannot proceed because rdToProcess("DE_Number") can no longer be read. How can I solve this? Many thanks and greetings for your help, Michel Tag: Null value Check in DataTable? Tag: 140594
  - 14
    - Console and Files How come line 1 will output garbage to the screen, but line 2 will output a good number to a file? How can I make line 1 out put a good number to the screen String* dayStr = System::DateTime::Now.ToString("dd"); Int32 dayInt = System::Int32::Parse(dayStr); Console::WriteLine("the day is {0}", __box(dayInt) ); // Line 1 . . . String* path = new String("_1D.txt"); // will read the time from a file FileStream * fs = new FileStream(path, FileMode::Open); BinaryReade* br = new BinaryReader(fs); Int32 day = br->ReadInt32(); fs = new FileStream(S"_1k.txt", FileMode::Create); //will write the time to another file BinaryWriter* bw = new BinaryWriter(fs); Br->Write( day); //Line 2 Tag: Null value Check in DataTable? Tag: 140587
  - 15
    - encrypt/decrypt function in asp.net 2 i am looking for code sampe in aso.net 2 for encrypt/decrypt of paswr d withought using any external DLL (judt to use existing net2 tools) thnaks i nadvance peleg Tag: Null value Check in DataTable? Tag: 140586
  - 16
    - SqlDependency.Start - Getting intermittent KeyNotFoundException I'm working heavily with query notifications in SQL Server 2005 and I intermittently get the following exception: System.Collections.Generic.KeyNotFoundException: The given key was not present in the dictionary. No one on the Internet seems to have ever encountered this. A partial stack trace appears below. It's partial in that I've ommitted a long set of calls from our interal app framework that are orthogonal to the problem. The NT user making these calls is a local administrator on the database server. The calls work a lot of the time, but break and seemingly random moments. We use a preconfigured SQL Server Service Broker Queue named QueryChangeMessages and a service called QueryChangeNotifications. Please help. Server stack trace: at System.ThrowHelper.ThrowKeyNotFoundException() at System.Collections.Generic.Dictionary`2.get_Item(TKey key) at SqlDependencyProcessDispatcher.SqlConnectionContainer.ProcessNotificationResults(SqlDataReader reader) at SqlDependencyProcessDispatcher.SqlConnectionContainer.SynchronouslyQueryServiceBrokerQueue() at SqlDependencyProcessDispatcher.SqlConnectionContainer..ctor(SqlConnectionContainerHashHelper hashHelper, String appDomainKey, Boolean useDefaults) at SqlDependencyProcessDispatcher.Start(String connectionString, String& server, DbConnectionPoolIdentity& identity, String& user, String& database, String& queueService, String appDomainKey, SqlDependencyPerAppDomainDispatcher dispatcher, Boolean& errorOccurred, Boolean& appDomainStart, Boolean useDefaults) at SqlDependencyProcessDispatcher.Start(String connectionString, String queue, String appDomainKey, SqlDependencyPerAppDomainDispatcher dispatcher) at System.Runtime.Remoting.Messaging.StackBuilderSink._PrivateProcessMessage(IntPtr md, Object[] args, Object server, Int32 methodPtr, Boolean fExecuteInContext, Object[]& outArgs) at System.Runtime.Remoting.Messaging.StackBuilderSink.PrivateProcessMessage(RuntimeMethodHandle md, Object[] args, Object server, Int32 methodPtr, Boolean fExecuteInContext, Object[]& outArgs) at System.Runtime.Remoting.Messaging.StackBuilderSink.SyncProcessMessage(IMessage msg, Int32 methodPtr, Boolean fExecuteInContext) Exception rethrown at [0]: at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg) at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type) at SqlDependencyProcessDispatcher.Start(String connectionString, String queue, String appDomainKey, SqlDependencyPerAppDomainDispatcher dispatcher) at System.Data.SqlClient.SqlDependency.Start(String connectionString, String queue, Boolean useDefaults) at System.Data.SqlClient.SqlDependency.Start(String connectionString, String queue) Tag: Null value Check in DataTable? Tag: 140578
  - 17
    - Internal .Net Framework Data Provider error 6. Hi I'm getting very occasional exceptions in an application when trying to open a SQLConnection. Does anyone know what this error means, or what I can do about it? The error has only occurred a couple of times, each time with a gap of more than a day, so I cannot replicate or even find a pattern other than it happening at the point where I open the connection. I've pasted the exception details below. Thanks Dan ---------------------- Source: System.Data Message: Internal .Net Framework Data Provider error 6. Stack: at System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject) at System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject) at System.Data.ProviderBase.DbConnectionPool.GetConnection(DbConnection owningObject) at System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection) at System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory) at System.Data.SqlClient.SqlConnection.Open() at.... etc.... Type: System.InvalidOperationException Tag: Null value Check in DataTable? Tag: 140577
  - 18
    - Problem in datagrid paging and checkbox Hi All, I have one issue in using the datagrid in the asp.Net. I have the checkbox column in the datagrid. And also having the paging option.I have selected two items in the page 1 and navigate to page 2.And i selected 1 item. The problem is when i come back to page one ,all the item was unchecked.Cos during the paging i need to bind the grid again from the database .Is there any way to bind the datagrid with one time data fetch from database. Tag: Null value Check in DataTable? Tag: 140571
  - 19
    - BackgroundWorkers and ADO.Net I have an app that allows the user to build a query and then click on a button to execute the query and the results are then used to fill a grid. Can I have the retrieval run in a backgroundworker and have a button that would allow the user to cancel the query if it is running for too long of a period? Is the BackgroundWorker able to populate a grid which is running in the primary thread? Bill Tag: Null value Check in DataTable? Tag: 140569
  - 20
    - Automatic filling fields Hi guys, could you please help me on my problem. >>>> --------------- <<<<<<<<< Datasource: MS Access 2003 Table1: Tbl_Employee Field1: Emp_name Field2: Position Field3: Contact# Field4: Address Table2: Tbl_Salary >>>> --------------- <<<<<<<<< Windows Form of Visual Basic.net i have a field Employee on the form, the problem is, i when i type the name of employee, i want the position, contact# and address to automatically fill my other fields and will save on my database Tbl_Salary. -- Message posted via DotNetMonster.com http://www.dotnetmonster.com/Uwe/Forums.aspx/dotnet-ado-net/200707/1 Tag: Null value Check in DataTable? Tag: 140566
  - 21
    - ObjectDataSource a little help I have something that works, but it only returns one row of data when i create an ObjectDataSource with it and bind it to a gridview so i need a little help with this (thanks) as simple as it gets 1. my class: Imports Microsoft.VisualBasic Public Class radioShowFiles Private _szFileName As String Public Property szFileName() As String Get Return _szFileName End Get Set(ByVal value As String) _szFileName = value End Set End Property End Class 2. the functions that allows it to bind: Public Function fn_getallRadioShows() As DirectoryInfo Dim ri As System.IO.DirectoryInfo = New System.IO.DirectoryInfo("c:\websites\arlnewlook\radioshows") Return ri End Function Function fn_rtn() As radioShowFiles Dim rsf As radioShowFiles = New radioShowFiles Dim ri As DirectoryInfo = Me.fn_getallRadioShows Dim diar1 As IO.FileInfo() = ri.GetFiles() Dim dra As IO.FileInfo For Each dra In diar1 rsf.szFileName = dra.Name Next Return rsf End Function End Class I know why it's only including the last row of data, but i am sorry to say i don't know what to do to change it! I know i'm very close. THANKS! KES -- Share The Knowledge. I need all the help I can get and so do you! Tag: Null value Check in DataTable? Tag: 140565
  - 22
    - combining datasets Hi, I have 2 datasets right now, say with the following structure: DataSet 1 has a row called ItemCode, index 1 DataSet 2 has a row called ItemCode, index 1 both are similar, but i need to merge them to make one dataset, which needs to have everything in DataSet1 plus anything from DataSet2 that's not in DataSet1 already. I'm not too familiar with working with Datasets, i know theres suppose to be a way to join them, can someone help out? Both have a ItemCode which is what needs to be used to make sure no duplicates from DataSet2 get into DataSet1. Thanks. Tag: Null value Check in DataTable? Tag: 140563
  - 23
    - DataAdapter with Parameter problem When I run the following code everything works fine (which proves the = stored procedure and the parameter: Dim cmdSQL As New SqlCommand cmdSQL.CommandType =3D CommandType.StoredProcedure cmdSQL.CommandText =3D "bdl_CustomerOrders_SELECT" cmdSQL.Connection =3D mcnnSQL Dim prm As New SqlParameter() prm.ParameterName =3D "@CustomerID" prm.Value =3D Me.cboCustomerSELECT.SelectedValue prm.Direction =3D ParameterDirection.Input cmdSQL.Parameters.Add(prm) mcnnSQL.Open() Dim dr As SqlDataReader dr =3D cmdSQL.ExecuteReader() While dr.Read Debug.WriteLine(dr.Item(0).ToString) End While dr.Close() However, when I run the following code I get the error message: Incorrect syntax near 'bdl_CustomerOrders_SELECT' at the last line: = sda.Fill(ds, "CustomerOrders") Thoughts anyone ? Dim sda As New SqlDataAdapter("bdl_CustomerOrders_SELECT", mcnnSQ= L) Dim prm As SqlParameter =3D = sda.SelectCommand.Parameters.Add("@CustomerID", SqlDbType.NChar, 5, = "CustomerID") prm.Direction =3D ParameterDirection.Input prm.SqlValue =3D Me.cboCustomerSELECT.SelectedValue sda.TableMappings.Add("Table1", "CustomerOrders") Dim ds As New DataSet() sda.Fill(ds, "CustomerOrders") Des -- = Using Opera's revolutionary e-mail client: http://www.opera.com/mail/ Tag: Null value Check in DataTable? Tag: 140562
  - 24
    - Question about TransactionScope Hi, Does TransactionScope need DTC in situations that the transaction is not distributed? I have a set of non-distributed transactions and I am not sure that TransactionScope is the best option for best practice perspective. Thank you, Max Tag: Null value Check in DataTable? Tag: 140560
  - 25
    - Strongly Typed DataSet -> Preview Data -> How to preview stored procedures with GUID parameter? Hi, In Strongly typed datasets, when we preview a table adapter query, we cannot preview a stored procedure query that has GUID parameter. The error complains that cannot convert a string to GUID. What is the proper format for GUID parameters? Of course I tried {.} format. Thanks, Max Tag: Null value Check in DataTable? Tag: 140556
- Next
  - 1
    - Typed DataSets ADO.NET 2.0 For a project I have a typed dataset created ( by dragging tables/ views and configuring the appropriate queries ). If the database schema for these tables is changed (e.g. few columns get added), is it possible to automatically refresh the DataSet. Right now, I see that the Fill query only has the previous columns selected, the new added ones do not appear. This is my first time using datasets, so wondering if the adapter queries can be refreshed somehow. Thanks. Tag: Null value Check in DataTable? Tag: 140553
  - 2
    - Check user input data exist in database: ERROR Dim retVal As Boolean = False Dim cnSQL As SqlConnection Dim cmSQL As SqlCommand Dim strSQL As String strSQL = "Select * From Table_Contacts where EmailAddress = '" & txtEmail.Text & "' OR Name = '" & txtName.Text & "';" cnSQL = New SqlConnection(thisConnection) cnSQL.Open() cmSQL = New SqlCommand(strSQL, cnSQL) Dim reader As SqlDataReader = cmSQL.ExecuteReader() If Not reader.HasRows Then retVal = False MessageBox.Show("No Record") Else MessageBox.Show(" already exists!", " ", MessageBoxButtons.OK, MessageBoxIcon.Error) retVal = True End If cnSQL.Close() cmSQL.Dispose() cnSQL.Dispose() retVal = True Can someone help me with this? I'm keep getting "already exist" even there is no matching record in the database. - Thanks Tag: Null value Check in DataTable? Tag: 140546
  - 3
    - Help with this Argument 'Prompt' cannot be converted to type 'Stri Hi; I am creating a windows app using ado.net 2.0 in the app I am connecting to a database by creating and then using a data provider factory. When I call sqlConn.Open() I get the follwoing message "Argument 'Prompt - cannot be converted to type String". What am I missing in my code ? My code follows: Here are the entries in my app.config file <configuration> <appSettings> <add key="provider" value="System.Data.SqlClient" /> </appSettings> <connectionStrings> <add name ="cnStr" connectionString = "Data Source=aServer;integrated Security=True;initial Catalog=GoodTable" /> </connectionStrings> </configuration> Here is how I call this in my app. : Try Dim sAttr As String = ConfigurationManager.AppSettings("provider") ' Dim dp As DataProvider = CType(Enum].Parse(GetType(DataProvider),sAttr), DataProvider) Dim cnStr As String = ConfigurationManager.ConnectionStrings("cnStr").ConnectionString ' Create the provider factory Dim df As DbProviderFactory = DbProviderFactories.GetFactory(sAttr) 'Connection here Dim sqlConn As DbConnection = df.CreateConnection() sqlConn.ConnectionString = cnStr Catch ex As Exception MsgBox(ex) End Try Try sqlConn.Open() Catch ex1 As Exception MsgBox(ex1) End Try Thanks for any suggestions ! -- Gordon Tag: Null value Check in DataTable? Tag: 140545
  - 4
    - What are the pros and cons in using Enterprise Library? I'm new to .net. It seems that those application blocks in Enterprise Library are very useful especially when one tries to build a new application. I want to know the pros and cons in using those blocks. Is MS going to release new Enterprise Library for future .net version/build? If I use the current version of the blocks, what happen when a new version comes out? Tag: Null value Check in DataTable? Tag: 140544
  - 5
    - NULL GUID fields in a Nested Query Hi there, Firstly, I hope this is in the right place! I have a problem with a nested query I am generating at runtime. My table (tblIndexValue) has values in every cell in all rows including the createdUserID column. The createdUserID's datatype is a GUID, and the table is in Access using Jet 4 to connect from .NET. Here is the query, as captured in the immediate window: - SELECT DocumentID, (SELECT value FROM tblIndexValue WHERE indexFieldID={7b47a555-9a8e-4336-acbf-12b170d46f71} AND departmentID={f7d75dd6-096c-43e1-9f25-285fbe74a547} AND DocumentID=Q.DocumentID) AS IV1, (SELECT createdUserID FROM tblIndexValue WHERE indexFieldID={7b47a555-9a8e-4336-acbf-12b170d46f71} AND departmentID={f7d75dd6-096c-43e1-9f25-285fbe74a547} AND DocumentID=Q.DocumentID) AS IVID1 FROM tblDocument AS Q GROUP BY Q.DocumentID; IV1, i.e. the value field (a text value) displays fine. However, IVID1, the createdUserID file (a GUID) only shows NULLS. If I run the inner query on it's own (i.e. SELECT createdUserID FROM .... substituting the Q.DocumentID for any of my documentID GUIDs) it displays as expected. Have I missed something here? Many thanks, David Tag: Null value Check in DataTable? Tag: 140539
  - 6
    - Flummoxed by Connection Problem Everything was working fine until suddenly this problem appeared from nowhere: Boot up the pc and go into SQL Server Management Studio. The database is present and the data can be accessed. Go into VB2005 Express and run the project. Everything works fine. Open Database Explorer and connect to the database and the following happens: 1. The project no longer works and this error appears at cnn.open() 'Cannot open user default database. Login failed. Login failed for user' 2. The database is no longer available in Management Studio. It appears but no longer has the little + sign next to it and the data is no longer accessible. If I try and view the database properties I get this error: Cannot show requested dialog. ADDITIONAL INFORMATION: Cannot show requested dialog. (Microsoft.SqlServer.Express.SqlMgmt) An exception occurred while executing a Transact-SQL statement or batch. (Microsoft.SqlServer.Express.ConnectionInfo) Database 'T:\VS_DATA\NORTHWND.MDF' cannot be opened due to inaccessible files or insufficient memory or disk space. See the SQL Server errorlog for details. (Microsoft SQL Server, Error: 945) The only way I can get out of this situation is to reboot my pc. I am ok as long as I don't try and connect to the database via Database Explorer. I have tried disconnecting from and even deleting the database in Database Explorer to no avail. HELP! Des -- Using Opera's revolutionary e-mail client: http://www.opera.com/mail/ Tag: Null value Check in DataTable? Tag: 140536
  - 7
    - Computed Field In Typed Dataset I have a list box that is bound to an object data source. I added a column, say ColumnC, to my typed data set (using the designer) and for the expression property I entered ColumnA + ': ' + ColumnB When I preview the data in the designer I get exactly what I want. Now I go over to the object data source on my web page, refresh it and refresh the schema. I can now see ColumnC as an option for the list box's data text field. However, when I run the page nothing shows up in the list box. However, when I view the page source, I see that the data value field did render. Next I put in a value (instead of the default DBNull) for the DefaultValue property. After going through the whole exercise of refreshing and such again, I run the page and the default value I put in is returned in the list box. Does anyone know what I missed? It must be something stupid. Thanks ... Tag: Null value Check in DataTable? Tag: 140531
  - 8
    - !VB.NET/Access: OleDbException (Data type mismatch in criteria expression) Dear ADO.NET experts! I hope someone can help me, as I've been tearing my hair out with this one all day! I'm getting very odd "Data type mismatch in criteria expression" errors that I can absolutely not nail down or debug at all. SCREENSHOT: http://img384.imageshack.us/img384/6564/oledbexceptionwb5.jpg Using: VB.NET (2005/.NET 2.0 & MS Access (2000) MDB) Process: This is a Wizard to make a monthly tax return. The user selects a date from a pre-filled drop-down combo box and clicks "Next" to go to the next page of the Wizard which loads payments (grouped by supplier) from the Payments table into a DataGridView. The tableadapter fill method is called, passing the From and To dates which are used to determine which payments are shown in the DataGridView on the next page. --- SQL (taken from the command property of the dataset designer): SELECT Subcontractor_ID, SUM(Gross) AS Gross, SUM(DirectCostOfMaterials0dp) AS DirectCostOfMaterials0dp, SUM(TotalAmountDeducted) AS TotalAmountDeducted, SUM(Net) AS Net FROM Payment WHERE (PaymentDate >= ?) AND (PaymentDate < ?) AND (Company_ID = ?) AND (MonthlyReturn_ID IS NULL OR MonthlyReturn_ID = '') GROUP BY Subcontractor_ID CODE: ' A tax month is from the 6th to the 5th of the following month _FromIncDate = DateAdd(DateInterval.Day, 1, DateAdd(DateInterval.Month, -1, CDate(cboMonthlyReturnPeriod.Text))) _ToDate = DateAdd(DateInterval.Day, 1, CDate(cboMonthlyReturnPeriod.Text)) ' Crashes on this line taPayments.FillForNewMonthlyReturn(DsInvoice1.Payment, _FromIncDate, _ToDate, My.Settings.CurrentCompany_ID) --- I have checked, double-checked and re-checked the data The table columns are defined as "DateTime" in Access, "DateTime" in the DataSet designer, and the values passed as parameters to the .Fill function are .NET Dates. This fault only happens on one customer's database, although this database appears to be no different to any of the other databases. I had thought perhaps this was to do with regional settings, but cannot find any evidence for this. What can I do to prevent this from occurring, and how can I debug the OleDbException to find out precisely what column the type mismatch is referring to? Warm Regards, Mike Wilson P.S. How does one go about subscribing to the Microsoft privatenews.microsoft.com newsgroups? We have an MSDN Subscription, but the links from the MSDN Subscriber Downloads page take you round in circles... (also x-posted to: microsoft.public.dotnet.languages.vb.data - but forgot to add this group) Tag: Null value Check in DataTable? Tag: 140530
  - 9
    - Ado.net and SQl view ??? Dear all, I would like to bind a datgrid control to an SQL view. How set SQL command type for a view ? Is it Text ? IN which form the sql view is returned, data set ? When I get my view bind to my grid, if new data is inserted in my database, does my view will be automatically refreshed with new data or dor I have to run the refresh my self with my datagrid ? The idea is that I would like that my grid data gets automatically updated if new data gets inserted and remove from my tables manged by the view thnaks for help regards serge Tag: Null value Check in DataTable? Tag: 140529
  - 10
    - Sending a set of data to a stored procedure Hello I need to write a stored procedure that executes a bunch of bulked and related(stock) trades. For example, the customer may have requested four trades to be placed. The trades are related because the money from selling one stock say needs to fund a new stock purchase. What is the recommened approach for sending the set of information to my stored procedure please? I can'r rely on stored proc parameters because the number of bulk trades varies and can be quite large. We have thought of two possible approaches: 1. Send a delimited string with special characters in the string signalling the begining of a new trade instruction. Clearly the stored proc is going to be complicated because of the string handling it is going to have to do 2. Insert the trade instructions into a temporary table and have the trade execution stored read the data from it during from its execution The target database is Sybase. Thanks Amir Tohidi Tag: Null value Check in DataTable? Tag: 140525
  - 11
    - Syntax error in INSERT INTO statement. vb.net I am using VB.net The Error message is :Syntax error in INSERT INTO statement. vb.net Could this be casused by my primary Key? if my primary key is "ID" and it is (autonumber). I tried inseting a blank field, number in a field, and the example is with out the field at all. INSERT INTO EST_TRI_Target_Data (TRI Facility ID, Facility Name, Street Address, City, State, Zip Code, County, Parent Company, Parent Company Duns, Mailing Name, Mailing Street Address, Mailing City, Mailing State, Mailing Zip Code, Public Contact Name, Public Contact Phone, Tech Contact Name, Tech Contact Phone, Tech Contact Email, Major Industry, Primary SIC Code) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?) This is the code Dim myConnection2 As New _ OleDbConnection( _ "Provider=Microsoft.Jet.OLEDB.4.0;" & _ "Data Source=C:\Documents and Settings\BookPC\My Documents\EST ltd USA\TRI data\TRI_data.mdb") 'Dim mySqlDataAdapter As SqlDataAdapter Dim strSelect2 As String = _ "SELECT * FROM EST_TRI_Target_Data" Dim dsCmd2 As _ New OleDbDataAdapter(strSelect2, myConnection2) 'myConnection2 = New SqlConnection("server=(local)C:\Documents and Settings\BookPC\My Documents\EST ltd USA\TRI data\TRI_data.mdb;Trusted_Connection=yes;database=TRI_data") 'mySqlDataAdapter = New SqlDataAdapter("Select * from EST_TRI_Target_Data", myConnection2) Dim myDataSet As DataSet = New DataSet() Dim myDataRow As DataRow ' Create command builder. This line automatically generates the update commands for you, so you don't ' have to provide or create your own. Dim myDataRowsCommandBuilder As OleDbCommandBuilder = New OleDbCommandBuilder(dsCmd2) ' Set the MissingSchemaAction property to AddWithKey because Fill will not cause primary ' key & unique key information to be retrieved unless AddWithKey is specified. dsCmd2.MissingSchemaAction = MissingSchemaAction.AddWithKey dsCmd2.Fill(myDataSet, "EST_TRI_Target_Data") myDataRow = myDataSet.Tables("EST_TRI_Target_Data").NewRow() 'myDataRow("TRI_Facility_ID") = "gs5436t3tsata" 'myDataRow("Parent_Company_Duns") = "db Enterprises" 'myDataRow("County") = "Nassau" myDataSet.Tables("EST_TRI_Target_Data").Rows.Add(myDataRow) myDataSet.Tables("EST_TRI_Target_Data").Rows(0)("ID") = dsCmd2.MissingSchemaAction Do While i < 21 i = i + 1 'SearchText = IIf(TextBox2.Text = "", "Tech Contact Name" & "</td><td><font color=#990000>", TextBox2.Text) SearchText = IIf(TextBox2.Text = "", DataFields(i, 0) & "</td><td><font color=#990000>", TextBox2.Text) gOptions = "rtfWholeWord" 'RichTextBox1.Find (FindString, StartPos, EndPos, Options) ' options: rtfNoHighlight,rtfWholeWord, rtfMatchCase TextLength = RichTextBox1.TextLength PosOne = RichTextBox1.Find(SearchText, 0, RichTextBoxFinds.NoHighlight) PosTwo = RichTextBox1.Find("</font>", PosOne, RichTextBoxFinds.NoHighlight) RichTextBox1.SelectionStart() = (PosOne + 29 + DataFields(i, 1)) FieldSize = PosTwo - (PosOne + 29 + DataFields(i, 1)) RichTextBox1.SelectionLength = FieldSize 'StoremyData.DesignMode.Tables(0).Rows(i)(DataFields(i, 0)) = RichTextBox1.SelectedText 'MsgBox(RichTextBox1.SelectedText) myDataSet.Tables("EST_TRI_Target_Data").Rows(0)(DataFields(i, 0)) = RichTextBox1.SelectedText 'myDataRow(DataFields(i, 0)) = RichTextBox1.SelectedText ' If PosOne = -1 Then ' MsgBox("Text not found") ' Else ' MsgBox("Text Found") ' End If Loop '*************************************************************************** 'myDataSet.Tables("EST_TRI_Target_Data").Rows.Add(myDataRow) Debug.WriteLine(myDataRowsCommandBuilder.GetInsertCommand.CommandText) dsCmd2.Update(myDataSet, "EST_TRI_Target_Data") myConnection2.Close() Tag: Null value Check in DataTable? Tag: 140523
  - 12
    - How to insert data row and reading out the ID of the new dataset Hello there, what is the best way to add an dataset and, then, to read out the ID value of the created dataset? ExecuteNonQuery() does not retrieve informations about the new ID of the dataset. Of course I can execute a statement like this: SELECT MAX(ID) from TableName, but this would not work, if the ID is of type string (this could be if someone likes to create a GUID string as ID value). Is there a possibility to work with a Dataset by setting the SelectCommand and UpdateCommand properties? How to I define the SelectCommand to fetch the ID of the new dataset? Regards, Norbert Tag: Null value Check in DataTable? Tag: 140522
  - 13
    - System.Transactions.Diagnostics.DiagnosticTrace throws an exception of initialization I use .Net 2.0 and connect to a database access, on the connection.open() I've this message "The type initializer for 'System.Transactions.Diagnotics.DiagnosticTrace' threw an exception" Code : public DataSet GetData(string SqlQuery) { using (OleDbConnection connection = new OleDbConnection(m_ConnectionString)) { connection.Open(); OleDbCommand command = new OleDbCommand(SqlQuery, connection); command.CommandType = CommandType.Text; OleDbDataAdapter adapter = new OleDbDataAdapter(command); DataSet ds = new DataSet(); adapter.Fill(ds); connection.Close(); return ds; } } Thanks for your help Tag: Null value Check in DataTable? Tag: 140521
  - 14
    - Sharing a DataSet among different Projects in a solution? I have genearated a Typed DataSet in a C# project and am able to use it in the from designer (I can drop a dataset Object from tool box and Set its DataSetName Property this typed dataset very normally) my Question is: Can I share this typed dataset with other projects in solution so I can use in their form designer? the reason I need this is I guess regerating a Type in another project (Assembly) actually makes a new type that is not considered the same by the .Net Runtime(even if the definition is exactly the same) Tag: Null value Check in DataTable? Tag: 140513
  - 15
    - From ADO.NET 1.1 to SQL 2005 and SQL 2008 Dear Sirs. I have Client Server Application on Client Side i have .NET 1.1 WinForm Application on Server Side i have SQL Server 2000 I'm using "OLE DB PROVIDER FOR SQL SERVER" for the Data Access 1) I'd like to upgrade Server Side to SQL Server 2005 (I will copy same database with users to sql2005) Should i update Clients to .NET 2.0 too ? Do i need install Native Client Lib on Client ? 2) when SQL Server 2008 is Relesed Can i connect to it from .NET 1.1 Application ? Thank you in Advance. Tag: Null value Check in DataTable? Tag: 140512
  - 16
    - finding column/row that causes System.Number.FormatException I'm reading in xml into a dataset. I'm having to mess around with the types of the xsd as well, since there are many null values in the data. The data is about 25% string, 10% int, the rest decimals. When I read this data in I frequently get a System.Number.FormatException. No surprise, since I'm messing with types in the xsd. But there is no indication of what row, column or string caused the error. So I'm doing this by process of elimination. Which is taking forever, due to the presence of nulls. I have no ability to modify the data really. Is there *any* way to set a breakpoint on System.Number.ConvertToNumber()? That might not be the exact method call... The exception has no data, the innerexception is null and the msg tells me basically nothing. Grr. Also, there are several thousand rows in about 85 tables. Tag: Null value Check in DataTable? Tag: 140510
  - 17
    - Strongly Typed DataSets and "Refresh the data table" Option Hi, Using Visual Studio 2005 and SQL Server 2005: I am trying to understand the stored procedures that Strongly Typed Datasets wizard generates for me. When we create a new strongly typed Datasets, and choose the following path: Choose connection-> Create new stored procedures -> Enter SQL (select * from tbl) -> Advanced Options -> Refresh the data table We have an advanced option to refresh the data table. When we check the option, the wizard adds a select statement to the end of SP_INSERT and SP_UPDATE. I don't understand how the result of the added select statement (to the insert and update stored procedures) are being read back by the internal DataAdapter. What makes the table adapter reads the result of the select statement after insert or update operations? A link to an online article would greatly help. Thank you, Max Tag: Null value Check in DataTable? Tag: 140509
  - 18
    - How save DataSet back to database? In my client Windows application, I am receiving a DataSet containing one DataTable. This comes to my client via the business tier on a different physical machine (we're using WCF if that matters). After I make changes to the data in the underlying DataTable, I send the DataSet back to the business tier. In the business tier, what should my code look like to persist the data up to the database? I'm assuming I need to do something like this: Dim Connection As New SqlConnection() Connection.ConnectionString = My.Settings.COWFeedyardConnectionString Dim Command As New SqlCommand() Command.Connection = Connection Dim DataAdapter As New SqlDataAdapter() DataAdapter.UpdateCommand = Command DataAdapter.Update(PenDataSet) .. but I get the errror: "Update unable to find TableMapping['Table'] or DataTable 'Table'." Thanks for any help, Ron Tag: Null value Check in DataTable? Tag: 140507
  - 19
    - How best to automatically update What is the best way to update a row in a DataGrid to the server database automatically whenever a user edits and then steps off the row they have been editing (rather like in Access). There doesn't seem to be an explicit RowEndEdit event so I was thinking of setting a flag on the CellEndEdit event and running the update off the RowLeave event if the flag is set. Thoughts anyone? Des -- Using Opera's revolutionary e-mail client: http://www.opera.com/mail/ Tag: Null value Check in DataTable? Tag: 140506
  - 20
    - HELP: CLR Trigger Fails when inside a user defined transaction! when I use my C# Application to update My DB using a transation I get the following Exception The context transaction which was active before entering user defined routine, trigger or aggregate "UpdateIntegrityCheck" has been ended inside of it, which is not allowed. Change application logic to enforce strict transaction nesting. What should I do? Tag: Null value Check in DataTable? Tag: 140503
  - 21
    - probleum in running asp i am facing the probleum in running asp onmy machine. i am using window xp 2000 and also i have installed iis on my machine but the asp does't work plese guide me how can i remove this probleum Tag: Null value Check in DataTable? Tag: 140502
  - 22
    - Can ADO to leave remnant data behind? I have encountered a situation where supposedly a function returning a datatable does not always clear the datatable before loading. This is according to a client, but I have not been able to verify that this is indeed what is happening ... client evidence seems to indicate this "type" of problem. For example, Dim dtMast As New dsMaster.MastDataTable For each drSetup in dtSetup dtMast = CreateTimeLine(drSetup.UniqueID, dtTemp1, dtTemp2) Next -------------- public function CreateTimeLine(...) as dsMaster.MastDataTable Dim dtMast As dsMaster.MastDataTable dtMast = New dsMaster.MastDataTable : : return dtMast end function -------------- Shouldn't the "dtMast = CreateTimeLine(drSetup.UniqueID, dtTemp1, dtTemp2)" always create a new dtMast such that all of the rows in the table are cleared when the CreateTimeLine is called each time in the loop? In walking through it in the debugger (VS 2003 Framework 1.1) it exhibits that behavior each and every time (i.e., the data from the prior loop is NOT in the database table), but has anyone encountered a situation where this does not occur with each function call ... essentially creating a table with rows from the last two loops instead of rows from just the latest? Thanks RonF Tag: Null value Check in DataTable? Tag: 140499
  - 23
    - EnterpriseLibrary. Return Recordset from oracle stored procedure Hi, I'm trying to use an EnterpriseLibrary 3.1 and return recordset from oracle database using stored procedure. As you may know, oracle stored procedures have out parameter of type cursor in order to return a dataset. It seems like I need to add a paramenter of type cursor to execute this stored procedure, but I can't find the type for the cursor. Does enterprise Library support this senario at all? Thanks everybody, Oleg Tag: Null value Check in DataTable? Tag: 140497
  - 24
    - Exception at SqlCommand.Connection.Open() in nested TransactionScope Hi, I have a VB class to update a MS SQL server according to different incoming parameters in .Net 2.0. However, I keep getting the error message "Communication with the underlying transaction manager has failed." when I have nested TransactionScope. I am quite new to this topic, please kindly correct me if my implementation is incorrect. Public Class UpdateAssignment MainFunction( param 1, param2) Try Using scope As TransactionScope = New TransactionScope() ..... ..... Function2(param2) scope.Complete() End Using Catch ex As System.Exception IsSuccess = False End Try End Function Function2 Try Using scope As TransactionScope = New TransactionScope() For i = 0 To 10 Function3 Next scope.Complete() End Using Catch ex As System.Exception IsSuccess = False End Try End Function Function3 Dim oSqlConnection As SqlConnection = New Data.SqlClient.SqlConnection Dim oSqlCommand As SqlCommand = New Data.SqlClient.SqlCommand Try Using scope As TransactionScope = New TransactionScope() oSqlConnection.ConnectionString = ConnectionString1 oSqlCommand.Connection = oSqlConnection ...'Add param here ... oSqlCommand.Connection.Open() oSqlCommand.ExecuteNonQuery() scope.Complete() End Using Catch ex As System.Exception IsSuccess = False Finally oSqlCommand.Dispose() oSqlConnection.Dispose() End Try End Function End The exception will occur at the oSqlCommand.Connection.Open() in Function3 when it loops for the second time. The error message is "Communication with the underlying transaction manager has failed." The inner exception is "Error HRESULT E_FAIL has been returned from a call to a COM component." Attached also the stack trace: System.Transactions.TransactionManagerCommunicationException was caught Message="Communication with the underlying transaction manager has failed." Source="System.Transactions" StackTrace: at System.Transactions.TransactionInterop.GetOletxTransactionFromTransmitterPropigationToken(Byte[] propagationToken) at System.Transactions.TransactionStatePSPEOperation.PSPEPromote(InternalTransaction tx) at System.Transactions.TransactionStateDelegatedBase.EnterState(InternalTransaction tx) at System.Transactions.EnlistableStates.Promote(InternalTransaction tx) at System.Transactions.Transaction.Promote() at System.Transactions.TransactionInterop.ConvertToOletxTransaction(Transaction transaction) at System.Transactions.TransactionInterop.GetExportCookie(Transaction transaction, Byte[] whereabouts) at System.Data.SqlClient.SqlInternalConnection.EnlistNonNull(Transaction tx) at System.Data.SqlClient.SqlInternalConnection.Enlist(Transaction tx) at System.Data.SqlClient.SqlInternalConnectionTds.Activate(Transaction transaction) at System.Data.ProviderBase.DbConnectionInternal.ActivateConnection(Transaction transaction) at System.Data.ProviderBase.DbConnectionPool.GetConnection(DbConnection owningObject) at System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection) at System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory) at System.Data.SqlClient.SqlConnection.Open() at UpdateAssignment.Function3(TAJobAction JobAction) in http://server//Project/App_Code/UpdateAssignment.vb:line 169 Any help is greatly appreciated. Thank you. Angela Tag: Null value Check in DataTable? Tag: 140492
  - 25
    - Copying Rows from a DataSet Is there an easy way to copy rows from one data set to another other than field by field copy? Thanks Brad Tag: Null value Check in DataTable? Tag: 140487

I have a DataRow in a DataTable. I want to know if there is a value. I
do this

if ( this.Rows[0]["Col_A"] == null )
{
throw new Exception ( "no" );
}
However this condition is never hit. Why?

Thanks.

Top

Re: Null value Check in DataTable? by Gregg

Gregg
Wed Jul 25 14:11:01 CDT 2007

> I have a DataRow in a DataTable. I want to know if there is a value. I
> do this
>
> if ( this.Rows[0]["Col_A"] == null )
> {
> throw new Exception ( "no" );
> }
> However this condition is never hit. Why?

Nulls in DataTable are stored as DBNull.Value (not *null* as you were
checking for).

So try this...

if ( this.Rows[0]["Col_A"] is DBNull)
{
throw new Exception ( "no" );
}

Top

RE: Null value Check in DataTable? by v-wywang

v-wywang
Thu Jul 26 03:48:24 CDT 2007

Hello Lucius,

The DBNull class represents a nonexistent value in ADO.net.

I agree with Gregg.
this.Rows[0]["Col_A"] is DBNull
should works fine in your case.

Have a great day,
Best regards,
Wen Yuan
Microsoft Online Community Support
==================================================
This posting is provided "AS IS" with no warranties, and confers no rights.

Top

Re: Null value Check in DataTable? by Larry

Larry
Thu Jul 26 14:07:36 CDT 2007

> I have a DataRow in a DataTable. I want to know if there is a value. I
> do this
>
> if ( this.Rows[0]["Col_A"] == null )
> {
> throw new Exception ( "no" );
> }
> However this condition is never hit. Why?

See "DataRow.IsNull()". Note that you should rely on strongly-typed DataSets
instead however. It's much easier and cleaner than the route you're now
taking. Each strongly-typed "DataRow" derivative also has an "IsNull()"
member for each (nullable) column of your tables. Using your example above
you would then just call "YourRow.IsCol_ANull()".

Top

RE: Null value Check in DataTable? by v-wywang

v-wywang
Mon Jul 30 06:17:23 CDT 2007

Hello Lucius,

Have you resolved the issue so far?
I just want to check if there is anything we can help.
Please feel free to update here, we are glad to assist you.

Have a great day,
Sincerely,
Wen Yuan
Microsoft Online Community Support
==================================================
This posting is provided "AS IS" with no warranties, and confers no rights.

Top