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- Previous
  - 1
    - How to rerun a sub with a SQL UPDATE statement IF not successful first time? Hi, I have a Sub procedure where I retrieve an xml string from a single field: (1) SELECT FieldA FROM tblTEST WHERE... (2) Append an element to the DOM (3) UPDATE FieldA... In the unlikely (but always possible) event that the UPDATE action bumps heads with someone else's UPDATE to the same field, how would I tell the sub to start from the beginning of the sub IF the UPDATE was not successful...sorry, but I have no clue...how do I even capture if the UPDATE doesn't happen? TIA, Kathy Tag: Ilistsource and Ienumberable Tag: 61079
  - 2
    - Search in Dataset I have a table with two columns: prod_id (primary key), prod_name. I filled my dataset with this table and bind two textboxs to the two columns. I am trying to search a specific product using its prod_name and I want to know the position of this row in datatable.rows. How can I do it? Thank you! Tag: Ilistsource and Ienumberable Tag: 61077
  - 3
    - Access dBase II files over a network share. Hello folks, I am trying to access a dBase III file on a network share via VB.NET code. For some reason it does not recognize the location as a network file in the OLEDb connection object. I keep getting this error: '\\Mike_desktop\avalon projects\FullData' is not a valid path. Make sure that the path name is spelled correctly and that you are connected to the server on which the file resides. Any help would be greatly appreciated. Thanks Mike Tag: Ilistsource and Ienumberable Tag: 61072
  - 4
    - Update UI with DS Changes I programmatically change the values in a dataset. However, the changes are not reflected in the UI. What am I missing. If I set the values in the UI controls the dataset is updated as expected. However, I am trying to decouple the logic from the UI (in case we switch from forms to ASP etc). Any help, hints, or comments are greatly appreciated. Cheers, Knut Vonheim Tag: Ilistsource and Ienumberable Tag: 61069
  - 5
    - DbNull Which is it? I have a scalar operation with a sql command, and I want to check for null values. If I check for dbnull it reads the command as a string. If I set it to a string, it reads it as dbnull. Dim dcOrdNumber As SqlCommand Dim null As DBNull If dcOrdNumber.ExecuteScalar() Is null Then ... ' Cast from type 'DBNull' to type 'String' is not valid. If dcOrdNumber.ExecuteScalar() = "NULL" Then ... ' Operator is not valid for type 'DBNull' and string "NULL". Tag: Ilistsource and Ienumberable Tag: 61064
  - 6
    - Strange behavior of my program Hello All, I wrote a program in which I have a OleDbConnection which I open in the contructor and close in the Destructor. When I run the program I get the following error Unhandled Exception: System.InvalidOperationException: Handle is not initialized . at System.WeakReference.get_Target() at System.Data.Common.WeakReferenceCollection.Close(Boolean flag) at System.Data.OleDb.OleDbConnection.CloseReferences(Boolean canceling) at System.Data.OleDb.OleDbConnection.DisposeManaged() at System.Data.OleDb.OleDbConnection.Close() at LoadCkpt.Finalize() If I remove the contructor and destructor and open and close the connection in my method only, then the program runs successfully. I don't understnad why is this error coming? Why is it that I can't open/close my connection in my contructor descructor? Has anyone else seen this kind of error? I will be very gratefull for your response. regards, Abhishek. Tag: Ilistsource and Ienumberable Tag: 61060
  - 7
    - web.config sql connectionstring problem Dear .Netters, Following is the code from my web.config file ========== <add key="SqlConnectionA.ConnectionString" value="workstation id=myPC;packet size=4096;integrated security=SSPI;data source=\"myPC\\myDB\";persist security info=False;initial catalog=telecomTimeSheet" /> ========== I call this connectionstring in my code behind file like this: ============ this.sqlConnection1.ConnectionString = System.Configuration.ConfigurationSettings.AppSettings.GetValues("SqlConnect ionA.ConnectionString").ToString(); ============= When I view the file I get the following error: ========= [ArgumentException: Format of the initialization string does not conform to specification starting at index 0.] System.Data.Common.DBConnectionString.GetKeyValuePair(Char[] connectionString, Int32 currentPosition, String& key, Char[] valuebuf, Int32& vallength, Boolean& isempty) +942 System.Data.Common.DBConnectionString.ParseInternal(Char[] connectionString, UdlSupport checkForUdl, NameValuePair& keychain) +116 System.Data.Common.DBConnectionString..ctor(String connectionString, UdlSupport checkForUdl) +114 System.Data.SqlClient.SqlConnectionString..ctor(String connectionString) +13 System.Data.SqlClient.SqlConnectionString.ParseString(String connectionString) +96 System.Data.SqlClient.SqlConnection.set_ConnectionString(String value) +11 ttsheet.timesheet.timeSheetForm.InitializeComponent() +1590 ttsheet.timesheet.timeSheetForm.OnInit(EventArgs e) +13 System.Web.UI.Control.InitRecursive(Control namingContainer) +241 System.Web.UI.Control.InitRecursive(Control namingContainer) +179 System.Web.UI.Control.InitRecursive(Control namingContainer) +179 System.Web.UI.Page.ProcessRequestMain() +174 ========= Any ideas in what I am doing wrong? SSP Tag: Ilistsource and Ienumberable Tag: 61057
  - 8
    - Help - Class Library Project Hellooooo, maybe MS guys can answer this please? How do I add SQL Tables from Server Explorer control, and then configure Adapter, and generate Datasets if I have a "class library project" Yes I know I can drag tables onto asp.net page, and on a WinForm - but I don't have these because my project is "Class Library Project" DLL. What's the recommended workaround? I need to be able to frequently update my code- gen'ed files. Thank you Tag: Ilistsource and Ienumberable Tag: 61053
  - 9
    - Help - Class Library Project Hellooooo, maybe MS guys can answer this please? How do I add SQL Tables from Server Explorer control, and then configure Adapter, and generate Datasets if I have a: <CLASS LIBRARY PROJECT> Yes I know I can drag tables onto asp.net page, and on a WinForm - but I don't have these because my project is "Class Library Project" DLL. What's the recommended workaround? I need to be able to frequently update my code- gen'ed files. Thank you Tag: Ilistsource and Ienumberable Tag: 61052
  - 10
    - Access2K Oledb DataView: DefaultValue Unique AllowDBNull properties When an OleDb dataview is instantiated using (Select * from MyAccess2000Table), why aren't the following datacolumn properties accurately exposed: Unique AllowDBNull DefaultValue Dim Col As DataColumn For Each Col In MyDataView.Table.Columns Col.Unique Col.AllowDBNull Col.DefaultValue Next When I test these values at runtime, they do not reflect the state of my Access table. Doesn't the JET4.0 Provider surface them to the DataView? TIA Tag: Ilistsource and Ienumberable Tag: 61042
  - 11
    - .Find Method w/multiple keys I've got a dataset (ratesds2) containing multiple relational tables (3) for which I'd like to find a single child record. Table(1) contains a single record for each product and table(2) contains details for the product. The product details table is "nested" based on the productID. Table one has a single key field (productID) and table two has two key fields with productID from table 1 being one of the two and the other a unique product attribute key. Dataset is correctly defined with the two primary key fields in table 2. All I want to do is retrieve a specific row from table 2 given the two key fields as follows and put the value of a single field into string variable; Sample Code ----------------------------------------------- Dim filterstring As String = "productid = '123'" Dim productdetailsview As New DataView productdetailsview = ratesds2.Tables(2).DefaultView productdetailsview.RowFilter = filterstring Dim foundRowsc() As DataRowView = productdetailsview.Find(New Object() "123", "C"}) dim attribiute_c as string = foundRowsc(0)("Details") This doesn't work. Any ideas? Tag: Ilistsource and Ienumberable Tag: 61041
  - 12
    - accessing column types without doing a query Is there a convinient way to access column types without having to actually perform a query? I know about the GetOleDbSchemaTable() function but I don't see anything about column types there. Thanks, Dave Tag: Ilistsource and Ienumberable Tag: 61029
  - 13
    - Storing changes to a dataset. Hello, I have posted the original problem to the newsgroup earlier this week and thought I would try again with my latest problems. I am developing a Data access component which is to access data from a Foxpro database (schema below) using the OleDbProvider. So far I have no problem getting information out of the database into a dataset but storing changes back to the Database is causing me alot of exceptions and I can't seem to understand why. Any help would be greatly appreciated. Thanks Bill I am developing in Visual Studio .Net 2003 (C#) and using Visual Foxpro 7.0 SP1. Database Schema ------------------ Table1 irow : integer [primary key] [default value calculated by stored procedure = column max value + 1] name : character (32) value : character (254) owner: integer [Foreign key to table 2] host: character (32) Table2: id: integer [Primary key] name: character(32) Description: character (254) Sql statements --------------- (Each is encapsulated with an OleDbCommand object generated by the visual studio designer) 1) SELECT table1.irow, table1.name, table1.value, table1.owner, host FROM table1, table2 WHERE table1.owner = table2.id AND table2.name = ? 2) INSERT INTO table1 (name, value, owner, host ) VALUES (?, ?, ?, ?) 3) UPDATE table1 SET name = ?, host = ? WHERE irow = ? 4) DELETE FROM table1 WHERE irow = ? Code ------ Originally I tried to use the OleDbDataAdapter that generated the DataSet, to store the changes. public virtual void SetParamter (DataSet dataset ) { OleDbCommandBuilder cb = new OleDbCommandBuilder( dataAdapter ); dataAdapter.Update( dataset ); } This generated the following exception: System.Data.OleDb.OleDbException: No value given for one or more required parameters. at System.Data.Common.DbDataAdapter.Update(DataRow[] dataRows, DataTableMapping tableMapping) at System.Data.Common.DbDataAdapter.Update(DataSet dataSet, String srcTable) at System.Data.Common.DbDataAdapter.Update(DataSet dataSet) at DataAccess.SetParameters(DataSet dataset) in e:\MyProjects\dataaccess.cs:line 168 The Table mapping is configured in the DataAdapter. I then tried creating my own commands and associating it with the DataAdapter, instead of using the command builder, and this resulted in the same exception. Next I tried to do the update myself by iterating through the dataset and calling the appropriate Add/Modify/Delete method depending on the DataRow's RowState. This generated exceptions as well, shown below along with each method's code. 1) Insert method: protected override bool AddRecord ( DataRow record ) { bool retVal = false; InsertRecordCommand.Parameters["ParameterName"].Value = record["name"]; InsertRecordCommand.Parameters["ParameterValue"].Value = record["value"]; InsertRecordCommand.Parameters["OwnerId"].Value = this.OwnerId; InsertRecordCommand.Parameters["Host"].Value = record["host"]; try { DbConnection.Open(); if ( InsertRecordCommand.ExecuteNonQuery() == 1 ) retVal = true; } catch ( Exception e ) { Console.WriteLine( e.ToString() ); } finally { if ( DbConnection != null ) DbConnection.Close(); } return retVal; } System.NullReferenceException: Object reference not set to an instance of an object. at System.Data.Common.ICommandText.Execute(IntPtr pUnkOuter, Guid riid, tagDBPARAMS pDBParams, Int32& pcRowsAffected, Object& ppRowset) at System.Data.OleDb.OleDbCommand.ExecuteCommandTextForSingleResult(tagDBPARAMS dbParams, Object& executeResult) at System.Data.OleDb.OleDbCommand.ExecuteCommandText(Object& executeResult) at System.Data.OleDb.OleDbCommand.ExecuteCommand(CommandBehavior behavior, Object& executeResult) at System.Data.OleDb.OleDbCommand.ExecuteReaderInternal(CommandBehavior behavior, String method) at System.Data.OleDb.OleDbCommand.ExecuteNonQuery() at DataAccess.AddRecord(DataRow record) in e:\MyProjects\dataaccess.cs:line 227 2) UpdateRecordCommand: protected override bool ModifyRecord( DataRow record ) { bool retVal = false; UpdateRecordCommand.Parameters["ParameterValue"].Value = record["value"]; UpdateRecordCommand.Parameters["Host"].Value = record["host"]; UpdateRecordCommand.Parameters["Irow"].Value = record["irow"]; try { DbConnection.Open(); if ( UpdateRecordCommand.ExecuteNonQuery() == 1 ) retVal = true; } catch ( Exception e ) { Console.WriteLine( e.ToString() ); } finally { if ( DbConnection != null ) DbConnection.Close(); } return retVal; } System.Data.OleDb.OleDbException: Syntax error. at System.Data.OleDb.OleDbCommand.ExecuteCommandTextErrorHandling(Int32 hr) at System.Data.OleDb.OleDbCommand.ExecuteCommandTextForSingleResult(tagDBPARAMS dbParams, Object& executeResult) at System.Data.OleDb.OleDbCommand.ExecuteCommandText(Object& executeResult) at System.Data.OleDb.OleDbCommand.ExecuteCommand(CommandBehavior behavior, Object& executeResult) at System.Data.OleDb.OleDbCommand.ExecuteReaderInternal(CommandBehavior behavior, String method) at System.Data.OleDb.OleDbCommand.ExecuteNonQuery() at DataAccess.ModifyRecord(DataRow record) in e:\MyProjects\dataaccess.cs:line 267 3) DeleteRecordCommand: protected override bool DeleteRecord( DataRow record ) { bool retVal = false; record.RejectChanges(); //To be able to get irow value from record DeleteRecordCommand.Parameters["Irow"].Value = record["irow"]; record.Delete(); //Mark as deleted again. try { DbConnection.Open(); if ( DeleteRecordCommand.ExecuteNonQuery() == 1 ) retVal = true; } catch ( Exception e ) { Console.WriteLine( e.ToString() ); } finally { if ( DbConnection != null ) DbConnection.Close(); } return retVal; } System.NullReferenceException: Object reference not set to an instance of an object. at System.Data.Common.ICommandText.Execute(IntPtr pUnkOuter, Guid riid, tagDBPARAMS pDBParams, Int32& pcRowsAffected, Object& ppRowset) at System.Data.OleDb.OleDbCommand.ExecuteCommandTextForSingleResult(tagDBPARAMS dbParams, Object& executeResult) at System.Data.OleDb.OleDbCommand.ExecuteCommandText(Object& executeResult) at System.Data.OleDb.OleDbCommand.ExecuteCommand(CommandBehavior behavior, Object& executeResult) at System.Data.OleDb.OleDbCommand.ExecuteReaderInternal(CommandBehavior behavior, String method) at System.Data.OleDb.OleDbCommand.ExecuteNonQuery() at DataAccess.DeleteRecord(DataRow record) in e:\MyProjects\dataaccess.cs:line 303 Tag: Ilistsource and Ienumberable Tag: 61021
  - 14
    - Formatting a MS Access date/time field in Windows Form column I read MS Access records in. The date/time field in my datagrid only shows the date...does not include the time. Is there a way to format or get the Column to show the time as well? This is in Windows Forms. Amil Tag: Ilistsource and Ienumberable Tag: 61015
  - 15
    - Populating a Combo Box from DataReader Hi! I am trying to populate a combo box using a data reader. I want to add the Item as well as the ValueMember. Will this do the trick? Do While oDr.Read cmbestudiante.Items.Add(oDr.Item("Estudiante_Apellido") + ", " + oDr.Item("Estudiante_Nombre")) cmbestudiante.ValueMember = oDr.Item("Estudiante_ID") Loop Tag: Ilistsource and Ienumberable Tag: 61013
  - 16
    - executing procedure several times Hi, I have to execute a stored procedure sp_StorProc several times. How do I batch it? I do not want to make a trip to the database at each execution. One approach is to concatenate all sp_StorProc calls into one string and then execute the command. However, this is not very elegant. Is there any other way? Regards, San Tag: Ilistsource and Ienumberable Tag: 61011
  - 17
    - Data access application block Hi, I'm using the SqlHelper class from microsofts data access application block and have problems when trying to call a stored procedure that has a TEXT parameter. I'm using the following environment: - SQL Server 2000 SP3a + Cumulative Patch (July 2003) - .NET 1.0 - Data Access Application Block 1.0 The method SqlHelperParameterCache.DiscoverSpParameterSet returns a SqlParameter with SqlDbType set to VarChar and Size set to Int32.MaxValue. The problem seems to be in SqlCommandBuilder.DeriveParameters. When calling the stored procedure with the automatically discovered parameter set, I get an SqlException with one of the following messages: - General network error. Check your network documentation. - A severe error occurred on the current command. The results, if any, should be discarded. In the servers event log, I can find the following error: Event Type: Error Event Source: MSSQL$MYSERVER Event Category: (2) Event ID: 17052 Date: 25.07.2003 Time: 16:33:35 User: N/A Computer: MYSERVER Description: Error: 17805, Severity: 20, State: 3 Invalid buffer received from client. Data: ... After reading some newsgroup posts, it seems to me that the problem also occurrs when using binary data. Is there a fix for these problems? Thanks, Martin Bischoff Tag: Ilistsource and Ienumberable Tag: 61007
  - 18
    - Data Access Application Block/Nested Dataset/Transactions I am in the process of writing some WEB Services that will receive a nested Dataset and have to apply any changes to the appropriate tables. I am planning on using the Data Access Application Block for my database calls. I have the UpdateDataset method working, but now I want to add transactional support. If the dataset contains changes to table1, table2, and table3 I want to wrap the updates in a transaction so I can roll back if necessary. Any ideas on how the application block handles this ? Do I have to modify the application block and add my own custom code ? Tag: Ilistsource and Ienumberable Tag: 61005
  - 19
    - OOP data storage vs. SQL calls I have a general question for which I would like to get some general input from the online community. I'm building an asp.net web application that will make extensive use of a SQL Server 2K database. One of the relationships in this database is many Tasks to a 1 Project. I can see two basic ways to manage this in my web application: The first is by creating a Project class and a Task class, and talking directly to the database with either -- meaning that on each page where I need data about either a Project or a Task, I make the stored procedure calls and add, modify, or delete the data appropriately. The other is to use the IEnumerable interface so that I can do clever things like Project.Tasks.Add() and Project.Tasks.Modify(), etc. But, in this model, it seems to make more sense to get all the necessary data upon instantiation of the Project class, and then carry it around in a Session object, and make database calls as I need to in order to keep the class and the database in sync. OK, so here's the question -- which is more efficient, and is there a point of diminishing returns for the preferred answer. In short, does it make more sense to have more database calls (potentially every page), or to have one big one, and carry the enumerated object around in Session, making calls only as necessary. Please note that I realize that number of concurrent users, number of layers in the architecture, etc. are all factors in making the decision . . . I'm looking for an "all other things being equal, x is more efficient, and here's why . . . " Anyone got an opinion on this? Any input is appreciated. Thanks, Vic Fees Tag: Ilistsource and Ienumberable Tag: 60993
  - 20
    - DataSets or Datareaders?!?! Hello Imagine you've an web page made by an ASP.NET web service and the asp.net page itself. All the Data retriving that the application does is made=20 using the webservice... when a web form is loaded the web=20 page calls several functions of the web service to get the options to populate drop down boxes etc... so far i've been using datasets returned from the web=20 service to the page. example: in a form on dropdown box could have a list of=20 clients. In the web page, on form load, i invoke a=20 webmethod of my web service that returns a dataset to the=20 page with a table consisting of those records fetched. In=20 the page I run over all the rows of the tabl=E7e and populate the=20 dropdown box. my doubt is: am i using ado.net right to do such things=20 or should i return a datareader for the web page instead of a=20 dataset?!?! is it good practice to works as i've been doing?!?! its' not a waste of resources to have things done that=20 way?!?! best regards Miguel Pais Tag: Ilistsource and Ienumberable Tag: 60984
  - 21
    - ADO.NET synchronization/concurrency Hello How can I insure that with an web app only one client access in write mode to a record in a table?!? My application scenario is the following: I've a web project that makes all the data retriving from the client and some client side validation. That web page often retrives data from an web service that, in each function, opens a database connection and gets the data, sending it to the client right after closing the connection... knowing that ADO.NET uses disconnected recordsets and with this kind of develloping architecture how can I insure concurrency to allow only on web client in write mode and the others in reading mode until the resource is free?!?! best regards Jorge Ribeiro Tag: Ilistsource and Ienumberable Tag: 60980
  - 22
    - Get a list of SQL Stored procedure parameters from database Hi, I am trying to modify a common function in SQLHelper class of the DAAB, which will return the SQL parameters for a stored proc. I am passing the connection string and the stored procedure name to it. How do I get the parameters from the database. The reason, I need to do this, because I am using Beta2 version and Deriveparameters function doesnot work in beta 2. How can I achieve the same functionality? Please Help!!!! Thanks in advance. Tag: Ilistsource and Ienumberable Tag: 60979
  - 23
    - another "InvalidOperationException: Timeout expired. The timeout period elapsed prior to obtaining a connection from the pool" error I've looked at all of the posts and on the web and found many people running into this same issue. I've take an look at my code (posted below) and it looks fine, but this is my first attemp at ADO.NET with Stored Procedures on SQL Server. I currently don't have any maxpool setting configured, so it's using what ever the default is (100 I believe). I've tried to use SQL Profiler to find out how many active connections there are as well as PerfMon and SQL Ent. Mgr., but I can't seem to find anything that shows any bad connections. Any guidance would be appreciated. Here's my connection string from the web.config file: <appSettings> <add key="ConnectionString" value="server=X.X.X.X;database=demo;uid=demo;pwd=12345;" /> </appSettings> where X.X.X.X is the IP of my remote Microsoft SQL Server 2000 - 8.00.760 on Windows NT 5.0 (Build 2195: Service Pack 4) ---------------------- code to get data into a DataList object ------------------------- Private Function getJobs(ByVal state As Integer) As DataSet ' Create Instance of Connection and Command Object Dim myConnection As New SqlConnection(ConfigurationSettings.AppSettings("ConnectionString")) Dim myCommand As New SqlDataAdapter("demo_GetJobs", myConnection) ' Mark the Command as a SPROC myCommand.SelectCommand.CommandType = CommandType.StoredProcedure ' Add Parameters to SPROC Dim parameterUserID As New SqlParameter("@UserID", SqlDbType.Int, 4) parameterUserID.Value = 1 myCommand.SelectCommand.Parameters.Add(parameterUserID) ' Add Parameters to SPROC Dim parameterState As New SqlParameter("@State", SqlDbType.Int, 4) parameterState.Value = state myCommand.SelectCommand.Parameters.Add(parameterState) ' Create and Fill the DataSet Dim myDataSet As New DataSet Try myCommand.Fill(myDataSet) Finally ' Close the Connection If myConnection.State = ConnectionState.Open Then myConnection.Close() End If 'the commands below were added to try to make sure the connection was closed and released myCommand.Dispose() myCommand = Nothing myConnection.Dispose() myConnection = Nothing End Try Return myDataSet End Function -------------------------------- end code ---------------------------------- Sincerely, Jeff Braun Tag: Ilistsource and Ienumberable Tag: 60977
  - 24
    - Insert into Access DB Using DataSet Hi... Here is my code and my problem is that it doesn't update DB. Langauage Used : C# OleDbAdapter customerDA= new OleDbAdapter("Select * from Cusomers",connection); DataSet customerDS = new DataSet(); customerDA.Fill(customerDS); DataRow customerRow = customerDS.Tables[0].NewRow(); customerRow["Name"] = "Kris"; customerDS.Tables[0].Rows.Add(customerRow); customerDA.Update(customerDS.Tables[0].Select(null,null,DataViewRoState.Adde d); connection.close(); Tag: Ilistsource and Ienumberable Tag: 60975
  - 25
    - DataSet Undo System I'm trying to make an undo system for my application using adonet. The idea is simple: before performing the undoable operation make the copy of dataset. If the user wants to undo the changes, then restore the data from the old dataset. I have the following issues: 1. Many objects througth the form have references to a dataset and/or it's tables. So it is not enough just to replace the _dataSet variable but I would need to rebind all controls. I don't like it. 2. Because of what I said in the first bullet I am trying to replace the data inside the existing dataset like this: if (_copyOfDataSet != null) { _dataSet.Clear(); _dataSet.Merge(_copyOfDataSet, false); } but I'm far from sure that it warks as expected. So far, my simple experiments have shown that it works but I'm looking for your ideas and suggestions. Actually there are n copies of dataset after the user performs n undoable operations so I'm not looking for Accept/Reject Changes solution which would support only one "undo" operation. Thanks Tag: Ilistsource and Ienumberable Tag: 60973
- Next
  - 1
    - Small ADO.NET design flaws Hello, Could someone from the ADO.NET design team respond to this , please : - why the IDbDataAdapter.Fill method does not have an overload which takes a DataTable parameter ? This is wierd considering that *ALL* the providers implement this overload. - why there isn't a ICommandBuilder interface ? Should we understand that is not required for a new a provider to implement the CommandBuilder functionality ? Thank you for your time. Cheers, Marius. Tag: Ilistsource and Ienumberable Tag: 60972
  - 2
    - Reading list of Providers for OLEDB Connection. This is a multi-part message in MIME format. ------=_NextPart_000_007E_01C35298.A4C757A0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi, I have requirement to retrive list of all providers supported in the = current system to prepare the OLE DB connection string. Is there any way in ADO.NET, i am using System.Data.OleDb as OleDb only = have the method to read the Schema information of any database = connection. Regards Rajeev ------=_NextPart_000_007E_01C35298.A4C757A0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=3DContent-Type content=3D"text/html; = charset=3Diso-8859-1"> <META content=3D"MSHTML 6.00.2800.1106" name=3DGENERATOR> <STYLE></STYLE> </HEAD> <BODY> <DIV><FONT face=3DVerdana size=3D2>Hi,</FONT></DIV> <DIV><FONT face=3DVerdana size=3D2></FONT> </DIV> <DIV><FONT face=3DVerdana size=3D2>I have requirement to retrive list of = all=20 providers supported in the current system to prepare the OLE DB = connection=20 string.</FONT></DIV> <DIV><FONT face=3DVerdana size=3D2>Is there any way in ADO.NET, i am = using=20 System.Data.OleDb as OleDb only have the method to read the Schema = information=20 of any database connection.</FONT></DIV> <DIV><FONT face=3DVerdana size=3D2></FONT> </DIV> <DIV><FONT face=3DVerdana size=3D2>Regards</FONT></DIV> <DIV><FONT face=3DVerdana size=3D2>Rajeev</FONT></DIV></BODY></HTML> ------=_NextPart_000_007E_01C35298.A4C757A0-- Tag: Ilistsource and Ienumberable Tag: 60970
  - 3
    - outer and internal loop inside a dataset How can I loop on a sorted datatable in order to sum an internal group? Here's what I mean: Dim tempacct As String For Each irow In dspslips.Tables(0).Rows tempacct = irow("bipad") & irow("issuecode") Do While irow("bipad") & irow("issuecode") = tempacct Loop Next The problem is the internal do while loop is endless because I don't see a way to increment irow inside a while loop. If I change it to a for each loop with, say, a .select("bipad = etc) it doesn't change anything because it doesn't move the outer loop except by one (next), whereas I want to make it move to the endo of the bipad/issuecode combination. I know I can set the table initially to 'distinct', but you would think there'd be a better way. Tx for any help. Bernie Yaeger Tag: Ilistsource and Ienumberable Tag: 60969
  - 4
    - Will Change in the Backend Table affects dataset automatically Dear All.. I'm in the development of a CRM application in VB DotNet. So after creating the Dataset for a particular table, If i'm changing the table structure in the database according to the clients need, will it automatically reflects in the Dataset.Structural changes means adding one more key to the combination primary key, or changing the order of the fields in the table or adding one more field. If the change will not reflectes automatically what i have to do for getting the latest changes in the dataset which is already created for that table. Thangs & rgds Bibin. Tag: Ilistsource and Ienumberable Tag: 60968
  - 5
    - DataAdapter not being populated using LIKE in select I am using Framwork 1.1, C#, and Access 2000. My table is called "sample1".If has only 1 column called "firstname" in it. There are 3 rows in "firstname": this is a dog I have no doggies there are only cats here Now, if I use the following select: SELECT sample1.firstname FROM Sample1 where firstname like '*dog*' 2 rows returned. If I use the following : OleDbCommand SelCmd = new OleDbCommand("SELECT sample1.firstname FROM Sample1 where firstname like '*dog*'",MyConn ); OleDbDataAdapter DAx = new OleDbDataAdapter(); DAx.SelectCommand = SelCmd; DAx.Fill( ds, "sample1" ); Zero rows are returned and no exceptions are thrown. Is there a problem i can't see in the parsing the provider is doing or do I need to change the syntax? Help! - thanks in advance. Tag: Ilistsource and Ienumberable Tag: 60966
  - 6
    - ADO.NET for ASP.NET? Hello, How do I add ADO.NET stuff (configure adapter, dataset, ect) onto a class library (DLL)? My project is web-based ASP.NET that uses data access dll. I am doing all database ops via that dll. I don't want to hand code otherwise autogenerated code. Most examples out there present solution for winForms. Thank you Tag: Ilistsource and Ienumberable Tag: 60961
  - 7
    - UnauthorizedAccessException in Connection Pooling Hi, I have a C# web application that refuses to run when connection pooling is turned on, and gives the following error message: MSG: UnauthorizedAccessException: Access is denied. SRC: System.EnterpriseServices STACK: at System.EnterpriseServices.Platform.Initialize() at System.EnterpriseServices.ResourcePool..ctor (TransactionEndDelegate cb) at System.Data.SqlClient.ConnectionPool..ctor (DefaultPoolControl ctrl) at System.Data.SqlClient.PoolManager.FindOrCreatePool (DefaultPoolControl ctrl) at System.Data.SqlClient.SqlConnectionPoolManager.GetPooledCo nnection(SqlConnectionString options, Boolean& isInTransaction) at System.Data.SqlClient.SqlConnection.Open() This is a very simple test page that simply tries to open a new SQL connection. The same page runs perfect in our development server. Any help will be appreciated. Thanks in advance. Tag: Ilistsource and Ienumberable Tag: 60960
  - 8
    - Presenting Error Messages Does anyone have a suggestion on how to present error messages in a "user-friendly" way. I know how to "handle" exceptions but what I want to do (at a minimum) is present useful feedback to the user rather than a cryptic, technical looking error message. For instance, if I update a table (using SQLDataAdapter.UPDATE()) and it returns a "Violation of UNIQUE KEY constraint..." message I want to tell the user: "User name entered already selected. Please select another" and not: "Violation of UNIQUE KEY constraint 'IX_Customer_Duplicate_User_Name'. Cannot insert duplicate key in object 'Customer'.Source: .Net SqlClient Data Provider" I can not find a way to find out what constraint was violated or what columns caused the error. I guess I could parse the error message and then "hard-code" a switch statement but that is not very "scalable" or "object oriented". Any suggestions? Tag: Ilistsource and Ienumberable Tag: 60958
  - 9
    - OraOLEDB.Oracle: Corrupt varchar2 column data in result rows Hi, We are using the Oracle OLEDB provider(9.2.0.2) and OLEDB data access components in .NET using C#. When we fetch more rows than the FetchSize connection string parameter (default 100), any varchar2 columns have corrupt data. Upon closer inspection the corrupt strings have the correct characters, it is that they are packed into 1 byte instead of being unicode (2 byte) characters. The first fetchsize number of rows are fine. Does anyone have a solution to this? We have the most recent Oracle Client and OLE DB provider. Just increasing the Fetchsize is not an option. Thanks, Rob Tag: Ilistsource and Ienumberable Tag: 60954
  - 10
    - DataReader Error On my ASP page I'm getting the following error: Invalid attempt to read when no data is present. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.InvalidOperationException: Invalid attempt to read when no data is present. Source Error: Line 98: db_rdr = db_cmd.ExecuteReader Line 99: If db_rdr.HasRows Then Line 100: lbl_portal.Text = db_rdr.GetString (0) Line 101: End If Line 102: Else As you can see, the reader has rows, but when I try to get the first column, it throes an error at line 100. Any help? This is the second time the DataReader is used in the same routine, and the first time, it works okay. Tag: Ilistsource and Ienumberable Tag: 60953
  - 11
    - Variable type What type of format is the field that is retrieved from the DB using a data reader? I can display the content into a msgbox but not a textbox. TEo Tag: Ilistsource and Ienumberable Tag: 60952
  - 12
    - Query a typed dataset I have an in memory dataset that I would like to query. 2 tables. I want to get results based on data from the 2 tables. How can I do this? Tag: Ilistsource and Ienumberable Tag: 60951
  - 13
    - Need advise on application architecture Hello all I am working on a large enterprise webapplication using VB.NET with an SQL Server 2000 database. There will be a lot of business logic and there currently are a lot of tables and data. For what I have read, strongly typed datasets are the way to go in this situation, since lots of my data needs to be bound to data aware controls and that guarantees the simplest/safest way around the concurreny problems I will be in. Now, how do I go from there? Should I create a stronly typed dataset for every table in the database? Or first create logical groups of data, in the way they will be used in my domain, using views? In the second case, how are relations kept by the datasets/classes? In a 1:n situation, does the 1 side contain a collection of objects of the n side? Or how is this done? Or should I entirely wrap the generated strongly typed datasets with a separate business logic layer? I read about it, but find that strange because the data (which it's all about here) is hidden and can no longer be bound easy to a datagrid for example. Also, there is room in the generated strongly typed datasets to contain business logic. But I guess that's only useful when the classes are not directly based on the databasestructure (1 class for every table). Any advise would be very appreciated. Thank you in advance Freek Versteijn Tag: Ilistsource and Ienumberable Tag: 60949
  - 14
    - Need advise on application architecture Hello all I am working on a large enterprise webapplication using VB.NET with an SQL Server 2000 database. There will be a lot of business logic and there currently are a lot of tables and data. For what I have read, strongly typed datasets are the way to go in this situation, since lots of my data needs to be bound to data aware controls and that guarantees the simplest/safest way around the concurreny problems I will be in. Now, how do I go from there? Should I create a stronly typed dataset for every table in the database? Or first create logical groups of data, in the way they will be used in my domain, using views? In the second case, how are relations kept by the datasets/classes? In a 1:n situation, does the 1 side contain a collection of objects of the n side? Or how is this done? Or should I entirely wrap the generated strongly typed datasets with a separate business logic layer? I read about it, but find that strange because the data (which it's all about here) is hidden and can no longer be bound easy to a datagrid for example. Also, there is room in the generated strongly typed datasets to contain business logic. But I guess that's only useful when the classes are not directly based on the databasestructure (1 class for every table). Any advise would be very appreciated. Thank you in advance Freek Versteijn Tag: Ilistsource and Ienumberable Tag: 60948
  - 15
    - Problem with Update Command in DataList I'm trying to use an UpdateCommand with a Datalist and am getting the following error: System.Web.UI.WebControls.DataListCommandEventArgs What does this mean I'm doing wrong? Thanks Much!!!! Lynnette BTW - Here is my code - if it helps: Private Sub DataList1_UpdateCommand(ByVal source As Object, ByVal e As System.Web.UI.WebControls.DataListCommandEventArgs) Handles DataList1.UpdateCommand Dim cnn As New OleDbConnection(Constants.OleDbConnectionString) cnn.Open() 'Dim iRin As Integer = DataList1.DataKeys(e.Item.ItemIndex) Dim iRin As Integer = Request.QueryString("intRIN6Digit") Try 'Delete Current Rec (old data) Dim sSQL As String = "DELETE FROM Radios WHERE intRIN6Digit = " & iRin & "" Dim objCommand As OleDbCommand = New OleDbCommand(sSQL, cnn) Dim objDataReader2 As OleDbDataReader objDataReader2 = objCommand.ExecuteReader 'Add New Info Dim strSQL As String = "SELECT * FROM Radios" Dim oCmd As OleDbCommand = New OleDbCommand(strSQL, cnn) Dim objDataAdapter As New OleDbDataAdapter() objDataAdapter.SelectCommand = oCmd Dim objDataSet As New DataSet() objDataAdapter.Fill(objDataSet, "Radios") Dim objTable As DataTable objTable = objDataSet.Tables("Radios") Dim objDataRow As DataRow objDataRow = objTable.NewRow() objDataRow("intRIN6Digit") = iRin objDataRow("strAssignment") = CType(e.Item.FindControl("txtAssignment"), TextBox).Text objDataRow("strCall") = CType(e.Item.FindControl("txtCall"), TextBox).Text objDataRow("strDivision") = CType(e.Item.FindControl("txtDivision"), TextBox).Text objDataRow("strDistrict-Section") = CType(e.Item.FindControl("txtDistrict"), TextBox).Text Dim cmd As New OleDbCommand(strSQL, cnn) 'cnn.Open() Dim objCommandBuilder As New OleDbCommandBuilder(objDataAdapter) objDataAdapter.InsertCommand = objCommandBuilder.GetInsertCommand() objDataAdapter.Update(objDataSet, "Radios") FillDataList() Catch lblError.Text = e.ToString Finally If Not cnn Is Nothing Then cnn.Close() cnn.Dispose() End If End Try End Sub Tag: Ilistsource and Ienumberable Tag: 60939
  - 16
    - ConnectionCheckForData ??? Hi, I'm working on a Web Service that is working fine, but sometimes I received this SqlException. Error #-2: Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding. on line 0. Error reported by .Net SqlClient Data Provider while connected to <SERVERNAME> Error made in procedure ConnectionCheckForData (CheckforData()). Sql Server error code: 0 StackTrace: at System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream) at System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior) at RCService.Db.ReaderInboxListSP(String userID, String account, DBName dbName) at RCService.Util.GetInboxList(String userId, String account) It hapens while executing sp with simple select statement. I would appriciate if someone could tell me somethnig more about this error. Enviroment: SQLServer 2000 SP 3, Windows 2000 Server. Oljeg Tag: Ilistsource and Ienumberable Tag: 60938
  - 17
    - SqlConnection dialog Hi, I writing a win32 app in which the user has to define the connection string for an sql connection. How do I show in runtime the dialog that is used to build a connection string in design time? TIA Tag: Ilistsource and Ienumberable Tag: 60935
  - 18
    - ADO UpdateBatch Hi I am looking to see how others have approached this. I have a large VB6 codebase using ADO. in most places we used updatebatch to update our recordsets. As I am looking to move to .NET and I look at ADO.NET I don't see equivilent functionality to the update batch method. I see that I now have to create update,insert,delete and select commands for my interactions woth the database. I can use a dataset and dataAdapter or use SQLCommands, etc but it just is a whole lot more code. anyone have a pointer to something I'm missing here? Thanks Sal Tag: Ilistsource and Ienumberable Tag: 60933
  - 19
    - C# and OLAP How to create an interface and access the OLAP Cubes(in SQL svr) from c#??? Please help, need ASAP. Thanks vinay Tag: Ilistsource and Ienumberable Tag: 60931
  - 20
    - DataException Hi all .. how can i work with DataException ???? i will try to explain my problem perhaps someone could help me ... i have a typeddataset, and when i try to add a new row, When i press the update button it throws an DataException, more precisly NoNullAllowedException. my question is ? how can i know which column is missing the value ??? do i have to check all columns one by one ??? with a for xxxx to xxx ??? thks JSB Tag: Ilistsource and Ienumberable Tag: 60930
  - 21
    - Multiple DataTable.Select Clauses I would like to find a specific row in my DataTable. In order to do that, I need to search the table for 2 values. Here's my code: string strSearch = "Artist_ID =" + artistID.ToString()+ ", ParagraphNum=" + paragraphNum.ToString(); Is this even possible? Tag: Ilistsource and Ienumberable Tag: 60929
  - 22
    - DataView.Sort Question Hi, I have a Dataview object which I use to bind to a Datagrid. It has 5 columns, 2 are string ,3 are numeric datatypes. If I use the 'Sort' Function of the Dataview Object, it sorts the string columns correctly, however the numeric columns are not ordered as they are when I do a Database select using an 'ORDER BY' command. I was wondering if I am missing something...how can I sort the numeric columns to be sorted numerically? rather than like a string. Cheers, Richard Tag: Ilistsource and Ienumberable Tag: 60926
  - 23
    - Determining parameters of a stored procedure How can I determine the parameters of a SQL Server stored procedure based only the name of stored procedure. Ideally it will be to obtain a collection of SqlParameters. Thanks! Tag: Ilistsource and Ienumberable Tag: 60924
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    - csv => dataset hello, i have an idea to access one exotic database from dotnet. the simplest solution seems for me to call database procedures through http as webpages. on server i plan to write program, what will translate returning data into some text format. as text format, i would like to use csv, not xml (or mix xml, as field description, and csv, as main data), as xml in this case looks too bulky and a waste of resources (this transport protocol will be invisible for programmer). but there are a little problem on dotnet side - how can i parse csv data here? if there are some csv parsers already, i wouldnt like to reinvent a wheel.. thnx Tag: Ilistsource and Ienumberable Tag: 60919
  - 25
    - DataAdapter Update question When you fill a typed dataset using a dataadapter, modify certain columns of data and call the update method to push the changes back to the server, does the dataadapter only update the columns that changed or does it update the columns that changed with new data and the columns that didn't change with the same data it had before? The reason I need to know is this: I have a table used in merge replication for SQL Server CE devices. The handheld users only modify certain columns in the field. I also have a program that pulls data from Intuit Master Builder which is a FoxPro based construction management program. I created a table on the SQL Server that includes all of the columns from the FoxPro dbf file and the other columns that we need to track (like these handheld modified columns). I have a program that runs on the server using a .NET framework filewatcher that watches the dbf files and if it detects a change it refreshes the SQL server table. This way I have one SQL Server table that has all of the data in one table without complicated joins. We can't send the foxpro tables to the handheld so by merging the foxpro data into SQL Server, the handheld users can have all of the foxpro data as readonly and all of the other data as read/write. The problem I am running into is that the handheld users will make changes during the day and when they sync up, all of their changes are lost. I checked the server and the replication monitor shows the data was conflicting and the copy on the server won. I can't keep going to the server to overwrite the confict changes everytime a user syncs, so I need to modify the code in my file monitor program. I am assuming that the file monitor program which updates the tables anywhere from several times a minute to once every two hours depending on what the users are doing in Master Builder, is refreshing the rows so many times that the replication manager thinks that the data in the row is newer no matter what. I want to minimize the amount of data the file monitor pushes into SQL server so I have created If Then statements to compare the foxpro data to the sql server data before it updates the dataset that I am pushing back to sql server. I need to know if the update method of the dataadapter pushes every column back to the server or just the columns that from the dataset that are marked as changed. I suspect that it pushes them all back because the command text associated with the update command of the dataadapter has all of the fields listed with parameters. Therefore, I suspect that if I want to minimize the amount of data that I send back, I would have to build my update command text dynamically in those IF THEN statements and then replace the command text of the adapter before calling the update method or call the executenonquery method of the command. Any comments will be appreciated. Kiere Tag: Ilistsource and Ienumberable Tag: 60918

I am a bit of a plodder so sorry if this sounds dumb.

I am trying to get data into a .NET web form datagrid from a vfoxpro 8 table
via the oledb driver. But when I debug I get a error message teling me: "An
invalid datasource is being used for datagrid1. A valid datasource must
implement either IListSource or IEnumerable."

I'm completely stumped, but I suspect the answer is so obvious I will feel a
complete idiot when I know it. Can anyone put me out of my misery?

Thanks in advance for any ideas.

John Wilson

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Re: Ilistsource and Ienumberable by John

John
Sun Jul 27 18:26:04 CDT 2003

Post the code, it could be any one of a hundred things you are doing wrong.

John

http://mallsocket.com

"John Wilson" <JW@AdviceNet.com> wrote in message
news:3f23c5c9$0$56605$bed64819@pubnews.gradwell.net...
> I am a bit of a plodder so sorry if this sounds dumb.
>
> I am trying to get data into a .NET web form datagrid from a vfoxpro 8
table
> via the oledb driver. But when I debug I get a error message teling me:
"An
> invalid datasource is being used for datagrid1. A valid datasource must
> implement either IListSource or IEnumerable."
>
> I'm completely stumped, but I suspect the answer is so obvious I will feel
a
> complete idiot when I know it. Can anyone put me out of my misery?
>
> Thanks in advance for any ideas.
>
> John Wilson
>
>
>

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