Null reference exception on main form. Help please...

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  - 1
    - ListBox component and underlying Items objects Hello, I've run into a brick wall in working with a standard ListBox. I'm loading lightweight objects into a ListBox component - call them Elements. The Element class has an ElementName property and an overridden ToString() method that displays the ElementName. When I load Elements into my list box Items collection, the ElementName displays and all is well. My problem occurs when I change an ElementName property programatically. The underlying Element does indeed change, but I can't get the text displayed the list box to reflect it! I can delete and re-add the Element and the change will show up, but neither ListBox.Update() nor ListBox.Refresh() change it. I've considered a custom draw method (which I may have to implement anyway). But is there another way of changing the text I'm overlooking? I'm not using data binding - can a ListBox programatically bind to its own Items collection? Any help appreciated. Thanks much Jim Stanley Media Services, Inc. Tag: Null reference exception on main form. Help please... Tag: 89108
  - 2
    - Is "colspan" in ListView possible? I am working with MS Visual studio C#.net, .net framework 1.1. Do you have an idea, how can I use the ListView (details display mode), that it does similarly as an html table do? Or there is a better container which would fit my needs? What I need in the ListView is: 1. Above some subitems, a common header should appear (above the actual column headers). 2. In some rows I don't have all details (texts for all subitems), but instead I have a commentary, common for some subitems. So, I would need a kind of "colspan" in a table. I would be grateful for any help/ Jola ---------------------------------------------------- I want to obtain that (example): <html> <table border=1> <tr> <th colspan='2'> </th> <th colspan='3'> Block 1 </th> <th> </th> <th colspan='3'> Block 2 </th> </tr> <tr> <th> Main item </th> <th> </th> <th> Subitem 1 </th> <th> Subitem 2 </th> <th> Subitem 3 </th> <th> </th> <th> Subitem 11 </th> <th> Subitem 22 </th> <th> Subitem 33 </th> </tr> <tr> <td> First entry </td> <td> </td> <td> 1284 </td> <td> 4352 </td> <td> 3214 </td> <td> </td> <td> 3421 </td> <td> 2412 </td> <td> 3421 </td> </tr> <tr> <td> Second entry </td> <td> </td> <td colspan='3'> here comes the commentary </td> <td> </td> <td> 4536 </td> <td> 9867 </td> <td> 3910 </td> </tr> <tr> <td> Third entry </td> <td> </td> <td> 3424 </td> <td> 3334 </td> <td> 3214 </td> <td> </td> <td colspan='3'> here comes the commentary </td> </tr> </table> </html> Tag: Null reference exception on main form. Help please... Tag: 89104
  - 3
    - RichTextBox with OLE functionality How do I implement the kind of OLE functionality found in MFC (CRichEditCtrl, CRichEditView and CRichEditDoc) in a RichTextBox? Are there any samples available (e.g. Wordpad for C#)? -- Arild Tag: Null reference exception on main form. Help please... Tag: 89103
  - 4
    - different levels of opacity in a Form I'm trying to create a form with different levels of opacity. Is this possible? Tag: Null reference exception on main form. Help please... Tag: 89100
  - 5
    - Text formatting in Menu Hi, I m using Menu in my vb.net application. I want to increase the text size, and font,change text color, increase the gap between two consecutive menu items. Is it all possible with the menu provided in vb.net? If no then how can I do this? Thanks in advance, RbanBph Tag: Null reference exception on main form. Help please... Tag: 89098
  - 6
    - Unable to set the ValueMember of a ComboBox to a non Browsable property Setting the ValueMember property of a ComboBox to a name of a property that is not browsable throws the following exception. System.ArgumentException: Could not bind to the new display member. Parameter name: newDisplayMember It works fine if I set Browsable to true. Has anyone encountered this before? Seems like a bug to me. This is how I set up the DataSource: ArrayList list = new ArrayList(); list.Add(new Person("John Doe")); this.comboBox.DataSource = list; this.comboBox.DisplayMember = "Name"; this.comboBox.ValueMember = "Name"; This is my Person class: public class Person { string _name; public Person(string name) { this._name = name; } [Browsable(false)] public string Name { get { return this._name; } set { this._name = value; } } } Here is the complete code listing: using System; using System.Drawing; using System.Collections; using System.ComponentModel; using System.Windows.Forms; using System.Data; namespace BrowsableAttributeTest { public class Form1 : System.Windows.Forms.Form { private System.Windows.Forms.ComboBox comboBox; private System.ComponentModel.Container components = null; public Form1() { InitializeComponent(); ArrayList list = new ArrayList(); list.Add(new Person("John Doe")); this.comboBox.DataSource = list; this.comboBox.DisplayMember = "Name"; try { this.comboBox.ValueMember = "Name"; } catch(Exception e) { MessageBox.Show(e.ToString(), e.GetType().ToString()); } } protected override void Dispose( bool disposing ) { if( disposing ) { if (components != null) { components.Dispose(); } } base.Dispose( disposing ); } #region Windows Form Designer generated code /// <summary> /// Required method for Designer support - do not modify /// the contents of this method with the code editor. /// </summary> private void InitializeComponent() { this.comboBox = new System.Windows.Forms.ComboBox(); this.SuspendLayout(); // // comboBox // this.comboBox.DropDownStyle = System.Windows.Forms.ComboBoxStyle.DropDownList; this.comboBox.Location = new System.Drawing.Point(24, 32); this.comboBox.Name = "comboBox"; this.comboBox.Size = new System.Drawing.Size(184, 21); this.comboBox.TabIndex = 0; // // Form1 // this.AutoScaleBaseSize = new System.Drawing.Size(5, 13); this.ClientSize = new System.Drawing.Size(292, 266); this.Controls.Add(this.comboBox); this.Name = "Form1"; this.Text = "Form1"; this.ResumeLayout(false); } #endregion [STAThread] static void Main() { Application.Run(new Form1()); } } public class Person { string _name; public Person(string name) { this._name = name; } [Browsable(false)] public string Name { get { return this._name; } set { this._name = value; } } } } Tag: Null reference exception on main form. Help please... Tag: 89097
  - 7
    - How? Using a custom TypeConverter in custom grid column style. I have bound a grid column to an enumeration data type. I derive from DataGridTextBoxColumn and override GetColumnValueAtRow and call a function I wrote to convert the enumeration value to a descriptive text for display in the grid cell. This works well. Even though the grid is not editable, and the column is readonly, when one clicks on the cell I get a type conversion exception. Looking at the stack I see Edit calls GetText which uses an "EnumConverter" to convert the descriptive text to an int32, which ultimately tries to parse the descriptive as an int32, and of course fails. I see that DataGridTextBoxColumn has a PRIVATE type converter member. I am seeking any pointers to examples, or samples, or explanations of how to intercede the conversion of the descriptive back to an enumerated value for my custom column type. I think I need to implement a type converter, but I don't see how to tie it in. Or even just to know "it can't be done" would be helpful. Tag: Null reference exception on main form. Help please... Tag: 89091
  - 8
    - check box in data grid How do you get a check boxs to appear as one of the columns in a datagrid? many thanks in advance Rod Tag: Null reference exception on main form. Help please... Tag: 89090
  - 9
    - No Touch Deployment and web server authentication Our app is No Touched Deployed from a web server. We leave the default Anonymous Access set on the web site. So far, 4+ client installs, no problems. I did an install on a client's web server last week, leaving Anonymous Access checked. I did some tests, all worked fine. Today, the app is crashing. I asked the client what's different on the web server. Per the client they can't leave anonymous access enabled so they unchecked it. So, now I am seeing 401 Returns Codes in the IIS log file for our files. How do folks work around this? It's a 2000 server box so this client cannot create another web site. I have no idea how to how to 'log in' to the web site when the client is making a request for a file. Tag: Null reference exception on main form. Help please... Tag: 89089
  - 10
    - How to Assign Connection Param for CrystalReportViewer?? Hello! I designed a crystel Report and run normally in my Computer. But when I bring it to the user computer (The SqlServer name is diffirent). So My Report is not working. I want to know how to do to assign the Connection param to CrystalReportViewer dynamically in order to run the report in anny Computer??? Thanks! Tag: Null reference exception on main form. Help please... Tag: 89088
  - 11
    - WebBrowser.CheckIfCreatedInIE() Hi Group. I'm developing a UserControl which is hosted inside Internet Explorer as an ActiveX control. Inside this control I need HTML rendering funtionality, which the new 2.0 WebBrowser control provides. The problem however, is that the WebBrowser control checks if it's inside another IE in the private WebBrowser.CheckIfCreatedInIE() method :( Is there a workaround, or some other way to get html rendering inside my ActiveX hosted UserControl?? Regards, Jim. Tag: Null reference exception on main form. Help please... Tag: 89087
  - 12
    - WinForms and AppDomains I have an application where I'd like to be able to run multiple instances of a Windows forms application. Due to a heavy hit in our application startup code it would be beneficial to be able to have a single process with multiple instances of the form. Additionally, it would be useful to be able to partition off each instance in it's own application domain. The current plan is for a module to handle starting a new thread which will fire up a new app domain and then load the form. This module will also handle firing up any new instances by creating a new thread and application domain. My concern is any issues surrounding the UI thread. I'm aware that only the thread that calls Application.Run should access any of the UI components. Typically you would only have one per process. In my situation I'll end up with multiple UI threads. However, each application domain will only have a single UI thread and only this thread will access any UI components. Is the application domain enough of a boundary for the UI threads or am I setting myself up for threading issues? Tag: Null reference exception on main form. Help please... Tag: 89082
  - 13
    - Context Menu for ActiveX control in VB.NET I'm using ActiveX control in my VB.NET project. It pops up but execution doesn't stop on Click event handler if I set a break point there. From http://www.developmentnow.com/g/29_2004_7_22_0_0/dotnet-framework-windowsforms.htm Posted via DevelopmentNow.com Groups http://www.developmentnow.com Tag: Null reference exception on main form. Help please... Tag: 89072
  - 14
    - Change value in bound ctrl when value of another bound ctrl change I have been developing WinForms apps in .NET for several years and have never discovered a good solution to this newbish problem. I frequently encounter a situation where I want to change the value of a control when the user changes the value of some other control and both controls are bound to the same row in a DataTable. For example, say I have a combobox of statuses and a textbox for comments but comments are not applicable for certain statuses. When the user selects one of these statuses I want to set the text of the textbox to an empty string. So I add a handler to the combobox's SelectedValueChanged event and set the TextBox's Text property to an empty string. Doing this seems to cause unpredictable behavior. Sometimes I get an empty textbox but the combobox is changed back to its original value and other times the textbox is not cleared. I assume one change gets pushed to the dataset and triggers a refresh of the controls from the dataset but I'm not really sure. I have worked around this by clearing the textbox when the combobox loses focus but users are never happy with this solution. Having encountered this problem again I thought I would see if anyone can tell me the "right" way to do this. Tag: Null reference exception on main form. Help please... Tag: 89071
  - 15
    - PropertyGrid steals focus Hi, I have a MDI child Form that contains a couple of custom controls (both Panel based viewers), a DataGrid, and a PropertyGrid. Try as I might to have the DataGrid receive focus when the MDI child Form is displayed, the PropertyGrid always grabs it. I have registered an event handler for the MDI child Form's Load event and VisibleChanged event and in both have tried to have the DataGrid request focus and set the CurrentCell to (0,0). This has not worked. Any ideas? Thanks. Tag: Null reference exception on main form. Help please... Tag: 89068
  - 16
    - datagrid event I have a parent and child datatable which i am viewing in a datagrid. does anyone know the event that is fired when the user expands the node to look at the child table? thanks. Tag: Null reference exception on main form. Help please... Tag: 89061
  - 17
    - GUI design guideline Hi! I'd like to know if Microsoft has published a guideline for GUI design for .NET applications (something about choosing the right flatstyle, fonts...). Thank you! Simone. Tag: Null reference exception on main form. Help please... Tag: 89059
  - 18
    - How to initialize hidden columns for newly added rows ? I want to allow the user to add new rows. Not all columns from the bound data tabled are mapped (i.e. there are hidden columns). But some of those columns do not allow null. When I add a new row I get an exception: A first chance exception of type 'System.Data.NoNullAllowedException' occurred in system.data.dll Additional information: Column 'REP_ID' does not allow nulls. Question is, How can I provide a proper row initialization when the grid creates a new row? That is, how can I detect the newly added row, and perform some initialization on the row's column values? Tag: Null reference exception on main form. Help please... Tag: 89058
  - 19
    - Sending e-mail through windows forms Hello all - I am very familiar with sending mail through asp.net (using the System.Web.Mail class), but I do not have experience sending e-mail through windows forms. I would assume the syntax is probably the same, but perhaps the class or method of calling it could be different? Can this be done in windows or do i need a web service(please, no)? Tag: Null reference exception on main form. Help please... Tag: 89057
  - 20
    - writing functions in dll (newbie) I have a task to write winform application while writing the functions that return information, in a dll - for example opening a file. can someone please give me an example for function that opens a file (openFileDialog) that will be written in a dll file? Thanks a lot Tag: Null reference exception on main form. Help please... Tag: 89056
  - 21
    - how to make a fullscreen window? I mean like VS.NET fullscreen windows? I was thinking: simply remove the border, set maximized and topmost. however I will have problem with dialog then (which would be behind my window, don't they?) (uh?!) any other idea? Tag: Null reference exception on main form. Help please... Tag: 89051
  - 22
    - Multiple Screen environment... Hello, My appliccation saves form size and positions whenever they are closed so they can be shown at the same size and position when opened next time. My problem in here is that when it is used in Multiple screen enviornment, I can't understand whether the window is in which screen and I also don't know how to set the position of a window other than the primary screen? Can anybody help me? Regards, Özden Irmak Tag: Null reference exception on main form. Help please... Tag: 89048
  - 23
    - Inherited Forms Hi all, Anyone can tell me if the derived forms need to call the constructor of the ancestor Form ? Also it's needed to call InitializeComponent() from Ancestor form or not ? Sample: public Class AncestorForm: System.Windows.Forms.Form { Public AncestorForm() //:base() needed or not ? { InitializeComponent(); } } public Class DerivedForm: AncestorForm { Public DerivedForm(): base() //:base() needed of not ? { InitializeComponent(); } } Tanks for your help Tag: Null reference exception on main form. Help please... Tag: 89044
  - 24
    - Load a form Hello, I have created an application in vb.net. I want to show a chaild form on main mdi form. Since form contains many controls it is taking too long to get displayed completely and it also flickers. I have tried SuspendLayout and Resume Layout methods, but was not helpful. Can I load this form in memory and then show it(using form.show method) so that it will be displayed in lesser time? Will it help me? How can I load the form in memory without displaying it? Pls. reply soon. Thanks in advance. --RbanBph Tag: Null reference exception on main form. Help please... Tag: 89039
  - 25
    - Printing from RichTextBox in .NET 2003 Hello. Is there any way to print text from a RichTextBox in C++ Windows Forms. I know that they got rid of this function but does anyone know about any classes that can be added to your project in order to print text from the richTextBox. I have tried using the built in windows forms print dialog and print function but it does not see text. Any help would be great. Tag: Null reference exception on main form. Help please... Tag: 89036
- Next
  - 1
    - Datagrid - Windows - DataGridBoolColumn - How can I disable all the check boxes in the column I tried boolCol.ReadOnly = true and a bunch of other things but can't get the check boxes for the datagrid's column for all rows to be disabled? Can someone tell me how to do this? MyGrid.ReadOnly = true; MyGrid.Click += new EventHandler(MyGrid_Click); MyGrid.CaptionVisible = false; tableStyle = new DataGridTableStyle(); tableStyle.MappingName = "MyItemsData"; tableStyle.AllowSorting = false; tableStyle.RowHeadersVisible = false; //MyCheckBox Check boolCol = new DataGridBoolColumn(); boolCol.MappingName = "MyCheckBox"; boolCol.HeaderText = "MyCheckBox"; boolCol.AllowNull = true; boolCol.NullValue = string.Empty; boolCol.FalseValue = false; boolCol.TrueValue = true; boolCol.Width = boolColWidth; tableStyle.GridColumnStyles.Add(boolCol); boolCol = null; Tag: Null reference exception on main form. Help please... Tag: 89035
  - 2
    - 3 windows, bring all to front Hi All, This should be pretty easy, and I'm sure there's a simple way to do it, but it's eluding me. The application has three windows open at all times. Needed functionality: a click on any of the three windows should bring the other two to the front as well so that they would all be above any other program windows. I've been messing with BringToFront and the Activated event but everything I do seems to lead into infinite loops. Hopefully one of you knows the 'right' way to handle this common problem. Thanks for any help! - Tom Tag: Null reference exception on main form. Help please... Tag: 89030
  - 3
    - How to impliment a wizard style SDI..... In VC++ using MFC I created a SDI app and in the CFormView I created a CPropertySheet added the CPropertyPage's to create a Wizard style SDI. How can I do something like this in WindowsForms? Thanks for you help?... Tag: Null reference exception on main form. Help please... Tag: 89028
  - 4
    - Win2k3 SP1 affects IEExec ?? Has anyone encountered issues running NTD apps on 2003 SP1? I have an application that runs fine when run from IE on 2003 SP0. It also runs fine when run from the file system (i.e., double-click the exe) on 2003 SP1. For some reason, when we run the same app from IE on 2003 SP1 machines, we're getting System.TypeInitialization exceptions in IEExec.exe . When examined closer by building the app with debug symbols on the server, it appears that (at least in this case) the TypeInitializationException is being caused by an exception as a Web Proxy Class (for a web service) is being initialized. The Message is "The type initializer for "System.Xml.Serialization.Compiler" threw an exception. The stack trace begins: at System.Xml.Serialization.TempAssembly.GenerateAssembly(XmlMapping[] xmlMappings, Type[] types, String defaultNamespace, Evidence evidence, CompilerParameters parameters, Assembly assembly, Hashtable assemblies) at System.Xml.Serialization.TempAssembly..ctor(XmlMapping[] xmlMappings, Type[] types, String defaultNamespace, String location, Evidence evidence) at System.Xml.Serialization.XmlSerializer.FromMappings(XmlMapping[] mappings, Type type) at System.Web.Services.Protocols.SoapClientType..ctor(Type type) at System.Web.Services.Protocols.SoapHttpClientProtocol..ctor() Has anyone seen behavior like this? Please post if further info would be helpful. Thanks in advance. Tag: Null reference exception on main form. Help please... Tag: 89027
  - 5
    - No Touch Deployment using HTTPS? Hi, I am trying to use NTD with HTTPS and get this error: "An execption 'System.Security.SecurityException' has occurred in IEExec.exe". I must access this exe through a https site. Is there a way to make this work? Also - I put the Application.exe in the Virtual Directory to use NTD. Do I also put the Application.exe.config in that directory as well? I haven't been able to find many detailed examples on how to use NTD. thanks in advance! Bill Tag: Null reference exception on main form. Help please... Tag: 89025
  - 6
    - why aren't changes in datasets recognized for bound controls? Hi, I've got a simple VB/Access app that binds text controls to various fields in a database table. Everything works fine, EXCEPT that when I call the Update method on the data adapter, nothing updates, because it thinks nothing has changed! If I make changes to the fields thru the bound edit boxes, and then check the "HasChanges" method on the dataset, it runs FALSE - even though the changes ARE reflected in the dataset's data! How do I fix this??? The Update calls do nothing even if I edit all the fields because the dataset won't recognized that anything has changed. The updates and everything work fine if I manually set new values into the fields; the update works and HasChanges returns true. ex.:dataset.tables(0).rows(0)("my field") = foo thanks! B Tag: Null reference exception on main form. Help please... Tag: 89024
  - 7
    - Help needed I have to crete a windows form within a thread. Can some post a code or direct me to some link to accomlish this? I have background service which needs to pop up this form which will be always on top of third party word editor. I am using ShowWindow and SetWindowPos WIn APIs. This is working on XP machines but I am having trouble with Windows 2000 machines. I have to make it working on windows 2000 machines as well. Any help would be appreciated. Thanks, Dinoo Tag: Null reference exception on main form. Help please... Tag: 89023
  - 8
    - How to track changes in a datagrid I'm developing a desktop app that displays several screens of of data in a two column fashion, the left column has the tiles and the right column has the input controls (textboxes, dropdowns, etc) for input. Typically the app is used to display preexisting data and the user would edit certain things. The data is saved on a network drive and can be edited by many users who have access to the drive (no concurrenct editing) so it needs to be able to track who changed what when. If a value is changed 10 times by 10 different user, it should be able to keep the history. I'm thinking maybe a DataGrid control is the best choice for displaying and accepting user input but not sure how it captures the change info. Could anyone point me in the right direction? Tag: Null reference exception on main form. Help please... Tag: 89022
  - 9
    - variable height TreeNodes in TreeView Is it possible to create a TreeView with variable height TreeNodes? For example, I may want to have text in a given tree node have hard return characters that wrap that node's text to next line? There is the TreeView.ItemHeight property but that only allows setting a height for all TreeNodes in the TreeView's underlying tree model (which is limited to TreeNode types of trees). Tag: Null reference exception on main form. Help please... Tag: 89019
  - 10
    - RegEx for Acceptions Numbers with Dot Hi using regEx class in c# can u tell me how to accept input string [0-9] and also accepting [dot][.] with 'n' times Tag: Null reference exception on main form. Help please... Tag: 89016
  - 11
    - Cursor "stuck" In Databound Control/Caching? I am having a strange issue and cannot solve it. Basically, I have a form that edits information in a database. This form has many different controls that are bound to a business object. When I first load the form to edit the info everything works properly. The process of loading the object also loads the object into cache (Isolated storage using Enterprise Library 2.0 caching application block). If I load the form again and attempt to edit a field (say notes a textbox) my cursor gets "stuck" in the text box and I cannot click on any other control in the form. However I can close the form with the X in the upper right corner and the keys still function properly (Enter saves the object and Esc closes the form). I have looked the stack trace but it is giving me nothing. I have no idea where to begin. Has anyone seen something similar or have any ideas what it might be? Any ideas how I can go about getting some info to solve the problem? Tag: Null reference exception on main form. Help please... Tag: 89013
  - 12
    - Form Display Hello, I have designed a form in vb.net. I have placed a tab control with 3 tab pages on the form. This tab control holds many controls in each tab page. This form is MDIChild form. I have not written much code on the form. Whenever I run the project, form is dipslayed as textboxes first then Data grid followed by another tab on the form and so on. Form does not display all the controls at once as complete form. What I should do in order to avoid this? Early response is awaited.. -RbanBph Tag: Null reference exception on main form. Help please... Tag: 89010
  - 13
    - key events doesn't work Hi. I got some problem with the key events, they doesn't rise. first I made a new win project in C#, and I set this.KeyPreview = true; also this.KeyUp += new System.Windows.Forms.KeyEventHandler(this.fClient_KeyUp); and then I test run the app, and the keyup event did evoke. then I added a brower control into the form private AxSHDocVw.AxWebBrowser mviewer; and test run the app again, but this time the keyup didn't evoke, I assume the the browser control took the key events, how do I let the parent form evoke the key events again? and the browser control seems don't have any key event handler, am i right? any help would be greatful. regards Steve p Tag: Null reference exception on main form. Help please... Tag: 89008
  - 14
    - Command button shortcut key Hi! i have a form in VB.Net with two command buttons CmdDelete and CmdAdd i need to add shortcut keys for example F8 for CmdDelete and F4 for CmdAdd but i don't have any code. could someone plz show me a sample code... Best wishes Tag: Null reference exception on main form. Help please... Tag: 89005
  - 15
    - Enter key in Text box I have a problem while using Enter key in text box. when user presses enter in the text box information of customer is loaded. and I have a clear button that clears all the controls on the form. first it works properly. then I click on some other button (say detail button) that opens some other form. after closing that form if clear the form using clear button and again enter Id in text box and press enter. it does not work instead click event of Detail button is fired. Again I clear the form and press enter in the text box then it works and shows the data in controls. It happens several times. I am able to trace that. Control does not enter in event handler of key press event when this problem happen. no error is coming in any of the processes and no default button is set. Any solutions to this problem? -- Regards, Lalit Bhatia Tag: Null reference exception on main form. Help please... Tag: 89003
  - 16
    - Custom Designer Hi, I'm writing a control called a validating submit button. Basically, you can tell it to validate a number of controls when the user hits this button. When they hit the button, it'll say, "You must enter yada yada..." and highlight the bad field. Ok, now that I've got that out of the way, I think this problem should be relatively easy. Basically, I created a special designer that was a form that had two lists, one of available controls, and one of controls it will validate, in order. It would then add these items an arraylist of the inherited button class. This seems to work fine! I can run my custom verb, have it open up and show all the items that are currently selected to be validated and all of that jazz, but it doesn't change the actual .vb file in the InitializeComponent sub of the test form. So basically, it can change all these values on the design-time copy of the actual control, but I can't figure out how to add code to the initialize component of the form that'll be using this control. I figure that this question ought to be rather easy, as being able to create a custom designer without being able to "save your changes," so to speak, is pretty useless, and probably a commonly asked question. Thanks for your time! Bryce Covert. Tag: Null reference exception on main form. Help please... Tag: 89002
  - 17
    - Windows XP doesn't restore its desktop background after closing a smart client app Hi, I have developed a smart client app and deployed it. In some of the client machines, they have set a desktop background image. When the user works with the smart client app and close after opening few windows forms, the windows xp desktop image have some rectangular borders all over it which were the size of the opened windows forms in the smart client. Can anyone tell me how to refresh the desktop background image in xp? Thank you. Tag: Null reference exception on main form. Help please... Tag: 88999
  - 18
    - Sometimes clicking on a TreeView node doesn't select it Hi; I have this case where when I click on a line in my TreeView, it selects it for a second, and then moves the selection back to the previous selection. Usually I have to click 3 times to get it to stick - then it's fine from then on. The tree is not set to accept drag/drop. HideSelection=false, otherwaise all is standard. This is the only event I have for the control - and it is the only control in the form: private void Tree_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e) { TreeNode node = treeDB.GetNodeAt(e.X, e.Y); if (node == null) return; RootNode root = node.Tag as RootNode; if (root == null) return; DoDragDrop(new DragDropData(app, root), DragDropEffects.Copy); } Any ideas? -- thanks - dave Tag: Null reference exception on main form. Help please... Tag: 88998
  - 19
    - How to get user information from the local system user accounts. I am hoping to be able to (easily) write a program that will go into the local computer (as long as you are logged in as the administrator) and get information about the existing user accounts. I want to do this for LOCAL accounts on computers that are NOT members of a windows 2000 domain. Can someone point me to the correct document/example that shows how this could be done. I have found many many many examples for Windows 2000 domains, but none for local system accounts. Tag: Null reference exception on main form. Help please... Tag: 88996
  - 20
    - Smart Client - Update from MSI Code? What code do I have to add to my application to get it to check for updates, then re-install itself via an MSI file? Any simple examples out there? Tag: Null reference exception on main form. Help please... Tag: 88995
  - 21
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.I created a VB.net Windows application using Form1.vb as my one and only
Windows form. When I go to run the application I receive the following
exception: "An unhandled exception of type 'System.NullReferenceException'
occurred in system.windows.forms.dll

Additional information: Object reference not set to an instance of an object."

When I opened up the Windows Form Designer generated code region I have a
constructor function that looks like this:
"Public Sub New()
MyBase.New()

'This call is required by the Windows Form Designer.
InitializeComponent()

'Add any initialization after the InitializeComponent() call

End Sub"

Any ideas on how to remedy this?

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Re: Null reference exception on main form. Help please... by Jon

Jon
Thu Jun 16 16:35:23 CDT 2005

Jim <Jim@discussions.microsoft.com> wrote:
> .I created a VB.net Windows application using Form1.vb as my one and only
> Windows form. When I go to run the application I receive the following
> exception: "An unhandled exception of type 'System.NullReferenceException'
> occurred in system.windows.forms.dll
>
> Additional information: Object reference not set to an instance of an object."
>
> When I opened up the Windows Form Designer generated code region I have a
> constructor function that looks like this:
> "Public Sub New()
> MyBase.New()
>
> 'This call is required by the Windows Form Designer.
> InitializeComponent()
>
> 'Add any initialization after the InitializeComponent() call
>
> End Sub"
>
> Any ideas on how to remedy this?

Firstly, find out exactly where the exception is. Look at the stack
trace. That should give you a good idea.

Could you post a short but complete program which demonstrates the
problem?

See http://www.pobox.com/~skeet/csharp/complete.html for details of
what I mean by that.

--
Jon Skeet - <skeet@pobox.com>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too

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