Unhandled exception after calling child form's Dispose().

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- Previous
  - 1
    - Chart control for Windows Forms hi, Looking for a reliable-easy to use Chart control. never used one before, so any advice / experience is greatly appreciated. Tag: Unhandled exception after calling child form's Dispose(). Tag: 84129
  - 2
    - Launch WebBrowser How can I launch a webbrowser from my windows forms applications? The reason I need that is because I have a DataGridView with links in one of the columns. When clicking on it I process the click and then want to start a webbrowser loading the site that the link was pointing to. Thanks, Rob Tag: Unhandled exception after calling child form's Dispose(). Tag: 84124
  - 3
    - Event on record change I have some controls on my form which are bound to a dataset and some which are not bound. But whatever record is displayed on the form, I want to populate those control (datetime, combo, etc.) with the data in the current record. What event can I do this in ? PositionChanged of bindingContext - is this called before the record is current or after ? if it is after, I can use this. Please advise. HS Tag: Unhandled exception after calling child form's Dispose(). Tag: 84122
  - 4
    - Bypass IE Print Dialog Hi, I am using ShellExecute() to print HTML files through Internet Explorer (to defalut printer). But I don't know how to bypass the Print Dialog. Any help/advise will be appreciated. Thanks in advance! DGU *** Sent via Developersdex http://www.developersdex.com *** Don't just participate in USENET...get rewarded for it! Tag: Unhandled exception after calling child form's Dispose(). Tag: 84118
  - 5
    - How to refresh SOME records in the datagrid but NOT SQL Server ? I am sure this is a dumb/simple question, but I am new to this stuff, so request for patience with me... I have OUTSIDE knowledge that there is activity regarding some records in a parent / child set of tables I am showing in what I want to be a read-only view in a grid. I have primary key values, but don't know if it is just a change to existing records, or if the record was recently inserted. I want to reflect these changes to the grid in realtime as they occur, by using the primary key to query certain records and get them updated in the datagrid. I started out binding the grid to a DataTable. But I had trouble detecting column sorts, and the need to show some status information for the current cell. I switched to using a DataView and that fixed that. Then I wanted to show work-order/line-item levels, and so I created a datarelation in a dataset, and bound to that, and this works (pretty good). I thought if I queried JUST the work order and line items I know have changed, this would be very efficient. I just need to integrate those data updates to grid. From docs it appeared that DataTable.LoadDataRow would allow me to import the values from the update query data set, and would then update my grid with additions and row value changes. But I get duplicate primary key errors, which suggests to me this is trying to update the database, rather than just my in-memory dataset and the display grid. This makes me wonder if I in any way change the dataset if it will be attempting to post those to the database underneath, which I do not want. Am I going to have to implement my own list structure to bind to the grid? If not, how is this done with datasets? Tag: Unhandled exception after calling child form's Dispose(). Tag: 84115
  - 6
    - BUG in Combobox.Location ? Hi, I want to draw combobox to bottom of form. I have following code : ComboBox C = new ComboBox(); C.Font=FontNormal; Size CSize=C.Size; C.Location = new Point(0,this.Height - CSize.Height); // this.Height is Height of parent control this.Controls.Add(C); By me it is correct but down part of my combobox is drawn out of control. Why ? Thank you Tag: Unhandled exception after calling child form's Dispose(). Tag: 84113
  - 7
    - SelectedIndexChanged event with listview I have a form with a listview to allow users to select an item. When they select one I fill in controls below it for them to modify the values. They can also just enter new values in the controls without selecting a listview item in order to insert new records. After entering new data if they select a row in the listview I prompt them to make sure they want to save the changes. If they select 'Cancel' I want to not highlight the newly selected row and leave the data in the detail controls as it was. Otherwise the new row is selected and the listview item is used to populate the detail controls. The problem seems to be that when I clear the selected items for the listview the selectedindexchanged event fires again. I get the yesnocancel prompt twice. If I step through the code in the debugger I only get it once. I tried using a bool to skip the handler when clearing the selection but it seems like the highlighting of the selected row then sometimes happens after the clearing so it ends up in the selected anyway. I tried playing with the clicked event and others and the events don't seem to always happen in a predictable order. Each thing I try seems to create new issues and it seems this shouldn't be this difficult. I've done similar things with the datagrid but would like to use listview. Basically want to be able to prompt the user sometimes when they select a new listview item and if they "cancel" I want to be able to clear the selection or set the selected item to a prior selected item without prompting them a second time. Any help would be appreciated. Thanks in advance. Jeff Tag: Unhandled exception after calling child form's Dispose(). Tag: 84112
  - 8
    - Databinding to Textboxes I have a windows forms that shows only one record at a time. The user selects the record he want via a combo box. Everything works fine for the first selection, however the textboxes do not automatically update their values when the combo box changes values. The textboxes are bound to a dataset. Here is and an example of what the databinding lookes like in designer: Text: DsEventPerson1 - tblSubject.FirstName When the user selects a new row in the combo box, the DsEventPerson1 is cleared and refilled. What must I do to get the textboxes to show the correct values for each record selected? -- wr Tag: Unhandled exception after calling child form's Dispose(). Tag: 84109
  - 9
    - Newbie question Hi, How I can get size of Graphics.DrawString in pixel ? Becuase after I draw string I need place after its combobox ... Thank you. Tag: Unhandled exception after calling child form's Dispose(). Tag: 84108
  - 10
    - change header text In my header on my grid i need to make the text dynamic, first is that possible and how can it be done? Tag: Unhandled exception after calling child form's Dispose(). Tag: 84106
  - 11
    - change header text In my header on my grid i need to make the text dynamic, first is that possible and how can it be done? Tag: Unhandled exception after calling child form's Dispose(). Tag: 84105
  - 12
    - Need to disable "Print progress" popup dialog have an app that does batch printing. The Dialog telling me which page is being printed keeps poping up. It's very annoying!! Any way to disable it?? Thanks in advance. Tag: Unhandled exception after calling child form's Dispose(). Tag: 84103
  - 13
    - Control Validating Event Odd Behavior I now know this event is quirky. I am seeing something odd, *though*. When I set a break point inside a validating Event Handler, I see the desired behavior when setting cancel = True. "If the test fails, you set the Cancel property of the Validating event's CancelEventArgs to True. This cancels the Validating event and causes the focus to return to the control. The practical effect is that the user cannot leave the control until the data is valid." However, when not running in debug mode I do not see the desired behavior when cancel = True. I am able to leave the control even though the data is not valid. Make sense to anyone? Greg Robinson Custom Data Systems, Inc. www.cds-am.net Tag: Unhandled exception after calling child form's Dispose(). Tag: 84102
  - 14
    - Calling .NET using COM I have a C# Windows Application that was built using an XML-based framework (It's fairly complex, but simplifies our development considerably.) We have recently integrated this application with a COBOL application, in that the COBOL application will call our .NET forms. I have discovered a few issues with this, and hope someone may be able to help in fixing them. Most of the problems seem to revolve around the Windows MessageLoop, threading and some third-party components (namely, Janus GridEx and Infragistics Toolbars). (I posted to their news forums, but have not had any luck there.) I think the problem may be more in how I am creating and using the thread. I have the code here that is used when a form is called from the COBOL application. One thing I have noticed is that if I call the form using System.Windows.Forms.Application.Run(_child) , the form works perfectly, but the user cannot do anything in the COBOL application - it's "frozen" until I close the .NET form. If I use the following code to call the form, the user can do stuff in the COBOL application, but the Tab, ESC, Alt, etc. keys do not function as expected on the third-party components, which may do something of their own with the keys. For example, the Janus Grid should Tab from column to column, but does not. Instead, it will tab from control to control. I have tried looking at various properties of the thread the form is on, the ApplicationContext, the Application, etc, but nothing seems to be different from one call to the next, except for the thread's ID. Any help would be greatly appreciated!! The code to create the thread is: _applicationcontext = new System.Windows.Forms.ApplicationContext(_child); ThreadStart _threadstart = new ThreadStart(this.StartMessageLoop); Thread _thread = new Thread(_threadstart); _thread.IsBackground = true; _thread.ApartmentState = ApartmentState.STA; _thread.Start(); Where _child is the form with the grid, and StartMessageLoop is: private void StartMessageLoop(){ Application.Run(_applicationcontext); } Tag: Unhandled exception after calling child form's Dispose(). Tag: 84100
  - 15
    - Winform with DirectX Video-Directshow Use I need to grab a video frame on a winforms app. The Microsoft oldway was with Direct Show filter as detailed in Microsoft DirectX 9.0 SDK Update (October 2004) GrabBitmaps Sample This C++ console application shows how to use the Sample Grabber filter to capture frames from a video file. What is the new way/right way to do this now? Am I suppose to use managed direct-x which supports the directshow filter? I need to do this in CSharp so are there special using statements that I need to access the direct show features of managed direct-x. Help anyone I am so confused about this. Thanks Tag: Unhandled exception after calling child form's Dispose(). Tag: 84098
  - 16
    - Problem with Opacity and Clipping on a textbox I have a derived textbox which draws an XP border around the control by catching the WM_NCPAINT message. The control works fine until the Opacity of the form is set to something other than 0. Setting the opacity to anything other than 1 causes all sorts of problems. For example, the DC returned by GetWindowDC is not aligned with the actual location of the window so the window is drawn in an incorrect location (it's offest by the width and height of the NC border), the drawing area in the DC is the wrong size so I cannot paint the entire NC area, the client area is not correctly positioned and the mouse hit testing is incorrect. In general things are a mess when opacity is set to anything other than 1. Any thoughts or comments? andrew using System; using System.Drawing; using System.Windows.Forms; using System.Runtime.InteropServices; using Barcap.GSL.Windows.Forms.Utils; namespace XpWindows.Forms.Controls { /// <summary> /// Represents a Windows XP style capable TextBox control. Displays in XP style if the /// AppController.Current.FormProperties.XPThemeStyle is set to other than "None". /// </summary> [ToolboxBitmap(typeof(XPTextBox),"Resources.XPTextBox.bmp")] public class XPTextBox : System.Windows.Forms.TextBox { #region Private Variables private bool _enableXPStyles = (AppController.Current.FormProperties.XPThemeStyle != XPThemeStyle.None); #endregion Private Variables #region Constructor /// <summary> /// Initializes a new instance of the XPTextBox class. /// </summary> public XPTextBox() : base() { } #endregion Constructor #region Protected Methods /// <summary> /// Expose whether XP styles should be used for rendering this control (derived from the app controller). /// </summary> protected bool EnableXPStyles { get { return _enableXPStyles; } } /// <summary> /// Override the paint message if XP styles are enabled. /// </summary> /// <param name="m">Windows message</param> protected override void WndProc(ref Message m) { const int WM_NCPAINT = 0x0085; // Base class implementation has to be called no matter what // because the scroll bars of multiline textboxes are drawn // in WM_NCPAINT base.WndProc(ref m); if ( _enableXPStyles ) { if (m.Msg == WM_NCPAINT) { using(Graphics gr = Graphics.FromHdc(Win32UI.GetWindowDC(this.Handle))) { // Draws a blue border around the textbox _DrawBorder(gr, 0, 0, this.Width - 1, this.Height - 1); // Draws over the textbox border using the textbox backcolor _DrawInnerBorder(gr); } } } } #endregion Protected Methods #region Private Methods /// <summary> /// Draw a rectangle border. /// </summary> /// <param name="g">The System.Drawing.Graphics object to be used to draw the rectangle.</param> /// <param name="x"></param> /// <param name="y"></param> /// <param name="width"></param> /// <param name="height"></param> private void _DrawBorder(Graphics g, int x, int y, int width, int height) { g.DrawRectangle(new Pen(XpBorderColor, 0), x, y, width, height); } /// <summary> /// Draws the inner border of the textbox control if XP style is enabled. /// </summary> /// <param name="g">The System.Drawing.Graphics object to be used to paint the inner border of the control.</param> private void _DrawInnerBorder(Graphics g) { using (Pen pen = new Pen(this.BackColor, 0)) { g.DrawRectangle(pen, 1, 1, this.Width - 3, this.Height - 3); } } #endregion Private Methods } } Tag: Unhandled exception after calling child form's Dispose(). Tag: 84097
  - 17
    - Possible bug using non system fonts Hi there. I've for the past few days been experimenting with the use of non system fonts via the PrivateFontCollection.AddFontFile() method. If i do something like this: private void button1_Click(object sender, System.EventArgs e) { System.Drawing.Text.PrivateFontCollection pfc = new System.Drawing.Text.PrivateFontCollection(); pfc.AddFontFile("FREE3OF9.TTF"); FontFamily fam = new FontFamily("Free 3 of 9", pfc); Font f = new Font(fam, 10F); this.listBox1.Items.Add(f); } and clicks the button about 5 times or so, the font objects get messed up and thrwos an exception in, among others, the name property. Any suggestions? Tag: Unhandled exception after calling child form's Dispose(). Tag: 84095
  - 18
    - The private components field: where is used? Hi there Every time I create a new Form in the VS 2003 IDE i see the following entry private System.ComponentModel.Container components = null; which constantly remains null, when I add controls (say a Button) or components (say Timer) on the Form. The protected Dispose() checks if (components != null) which always returns false. Questions: 1. Where and when that private "components" field is used? 2. If it is always null a. can I delete it safely? b. why I don't see any compiler warning? Also, that same declaration private System.ComponentModel.Container components = null; is done by the IDE when I create a new Component or CustomControl file. But I don't intend to use it. Do I really need it? Best regards Theo ------------------------ Theo Bebekis Thessaloniki, Greece ------------------------ Tag: Unhandled exception after calling child form's Dispose(). Tag: 84094
  - 19
    - Winforms design with class in nested namespaces hi i am working on a gui for a bigger project using managed c++ and wanted to put it in the namespace hierachy under cubes::gui so i did this in my form.h namespace cubes{ namespace gui{ public class [...] }} but now the design view does not work... it only does with ony one given namespace like ... namespace gui{ public class [...] } how do i make my forms live in cubes::gui and still be able to use the form designer? regards Florian Demmer Tag: Unhandled exception after calling child form's Dispose(). Tag: 84092
  - 20
    - Capturing user interaction Hello NG, in my MDI-App, I'd like to checkfor how long the User hasn't done anything (moved the mouse, pressed a key) so that I can do some stuff after a given amount of idle time. My first idea was to save the current time in a variable every time the user moves the mouse or presses a key so that i can use that variable to calculate idle time. I ran into a problem at the very start though. The MouseMove Event of my MDI parent form is never fired. Is that standard behaviour for MDI containers? What would be an elegant way to capture the point in time of the last user interaction? Tag: Unhandled exception after calling child form's Dispose(). Tag: 84088
  - 21
    - Beginners Question Form Sizing Hi I am writing my first .DotNet application out of the Wrox Professional 2003 Book. I would like to ascertain the screen size in use and size my forms accordingly but that topic does not come up in the relevant chapter on forms How do I get at the relevant computer environment information to size the MDI form Roger Stenson Tag: Unhandled exception after calling child form's Dispose(). Tag: 84087
  - 22
    - Monitoring MouseMove anywhere within the screen. Is it possible to track a general "MouseMove" event that monitors mouse movement anywhere within the screen, not just within a the scope of a Control? I'm writing logic that resizes a form on mouse move, but I'm finding that when the mouse falls out of the size of the control/form I lose the MouseMove event, and the resize operation ends. Hope that makes sense. Cheers everyone! ==== Phil Tag: Unhandled exception after calling child form's Dispose(). Tag: 84085
  - 23
    - I have to re-build project to see changes at run time I have one project that must be rebuilt instead of just built in order for changes to be seen. This is the startup project. I am running in debug mode, and the project is checked to build in this configuration thru config mgr. what am i missing? Tag: Unhandled exception after calling child form's Dispose(). Tag: 84076
  - 24
    - Strange combobox focus/selectedtext issue Hi, I have a MDI app with a child form that has tab pages. In the main (first) tab page, there is a panel, on this panel, there are a few text boxes and one readonly combobox. The controls on this form are bound to a datatable in a dataset. When this form loads initially, the main (first) tab is shown and the readonly combobox's text is selected. It shouldn't be, and I can't figure out how to deselect it. If I click the the second tab page and then come back to the main (first) tab page, the combobox's text is no longer selected. Any idea how to prevent this or wprk around it? Thanks, Josh Tag: Unhandled exception after calling child form's Dispose(). Tag: 84073
  - 25
    - listview scrollbar range not correct I implemented a double buffered listview to eliminate flicker. I set the following styles, then overrode OnPaint and did the drawing. Everything looks great! However, if I change the font from default, the column headers are not drawn with the new font and worse yet the scrollbar doesn't know that font height has changed and I can never scroll to see the last few items on the list. Short of adding my own scrollbar, is there a way to let the column headers and scrollbar know about the new "range" when the font is changed? SetStyle(ControlStyles.DoubleBuffer, true); SetStyle(ControlStyles.UserPaint, true); SetStyle(ControlStyles.AllPaintingInWmPaint , true); Tag: Unhandled exception after calling child form's Dispose(). Tag: 84064
- Next
  - 1
    - How to access RadioButton's round cycle/dot graphics? What I am trying to do is to change the round button background to grey and still keep the text label black, by overriding the "Enabled" property. The purpose is to keep the radio button reader-friendly while keep it non-editible. Somemhow I didn't find any property exposed to change the button's background color. Well, there IS a backcolor property but the color applies to the whole button area including the text area. I want to change the little round-dot button only. Thanks strout Tag: Unhandled exception after calling child form's Dispose(). Tag: 84062
  - 2
    - Microsoft: Help with OLE documents... Hi all. I have an application to draw and design different documents, that supports linking and embedding of other documents (like, for instance, Corel Draw or Word). Then, the user can print their designs "WYSIWYG", so I load the external document inside an OLE document container control (VB6), get a handle to the object and invoke OleDraw with the hDC that I want the object in. This have been working excellent, and this application is largely distributed among our clients. The problem is we want to migrate to .NET (any language, VB, C#, C++, ...), but there's no OLE container that lets me obtain a handle to an OLE document. I know you could import COM and ActiveX, but this particular control (included in VB6) CANNOT BE IMPORTED NOR INSERTED in .Net. Microsoft calls this a "migration issue" and warns us about it, but how, then, can I draw an Ole document inside our application (let alone open, edit, update, etc)? Is Microsoft planning to update this component for VS.Net 2005? Or is there an alternative? I know I could load an OLE document "the hard way", but those are methods so obscure, I get lost before even starting to insert the document in a container... If this is the only solution, is there an easy (as easy as this can be) example that can lead me to accomplish the insertion of a document inside mine? I know it can be done, because RTF editor lets you do it. It even lets you open and edit the document, and "paste special", but I don't seem to accomplish getting a handle to any of those inserted objects... Thank you for your time, VBen. Tag: Unhandled exception after calling child form's Dispose(). Tag: 84059
  - 3
    - Form as a control? Hi, Is there a way to have a form as a control? Here's what I want to do: I have a datagrid which displays various information. However, I want to use it in multiple locations within the same application. Instead of creating an instance of the grid and linking up the same data on each form, I want to have a "floating" form which contains my grid in my application. When a new form needs this grid, I would, say, take the form (with the grid) and add it to a panel as a child control ... does this work? Is this even a good approach? Any examples? Thanks in advance, Chris Tag: Unhandled exception after calling child form's Dispose(). Tag: 84058
  - 4
    - App.config Problem when launched from IIS not locally I have an application that when launched under Windows XP, from an IIS web server, will not read values from the app.config file. I have looked at the IL code and attempted to reconstruct what AppSettings["key"] does. I can create a webclient and download the app.config file and can even display it in my application. However the AppSettings["key"] approach yeilds a null value. It is not a security problem on the web server (at least that I can see), I can download the app.config file using IE, or through code. If I run the application from my local machine this problem does not happen Furthurmore I have disabled DotNet security by using [caspol -s off] so I can't see any security problems. Please help. This is a very important application for our organiztion. Tag: Unhandled exception after calling child form's Dispose(). Tag: 84057
  - 5
    - adding items to listbox with extra data similar to databinding to dataview since you can't change items in a listbox that is databound, i have to add & remove items using its items collection. The thing about this is that with databinding, each item in the list can hold all the info for a particular datarowview and can be accessed by converting the list item back to this object. The real thing i need to do is be able to have the list item's text displayed correctly, then behind the scenes, i need to be able to access an ID field from the data record associated with the item so that i can then do an update to the db with the selected items of the list. How do i save this extra data without databinding? thanks Tag: Unhandled exception after calling child form's Dispose(). Tag: 84053
  - 6
    - Button images I'm relatively new to programming in C#, so I'm probably missing something obivous. I've got several buttons on a form that I assign an image to when the user clicks each button. That works fine. If the user clicks the button again, I want to remove the image and just display the text in the button's Text property. How can I remove the image from the button? Thanks for any help. Mike Tag: Unhandled exception after calling child form's Dispose(). Tag: 84052
  - 7
    - BIg Problem Hi, Hi testing the Visual Studio 2005 Beta 2, i'm developed one application and save this project, when close the visual studio and reopen in another time with the application i produce this error OBJECT REFERENCE NOT SET TO AN INSTANCE OF AND OBJECT LINE 0 COLUMN 0 And not is possible open the project Thanks in advance Euclides Tag: Unhandled exception after calling child form's Dispose(). Tag: 84047
  - 8
    - Config problem: appSettings not found by other dll's I am running a wizard style application which uses other assemblies. One of these assemblies uses an appSettings section for configuration. My understanding is that the configuration systems uses a config file named after the hosting process executable? However, this isn't being picked up from this file.. Does anyone have any suggestions as to how to solve this one? Dirc Tag: Unhandled exception after calling child form's Dispose(). Tag: 84046
  - 9
    - checkbox column in datagrid - event handling I have a datagrid with a checkbox column. How can I make a messagebox appear if a cell with the checkbox gets checked or unchecked? thank you in advance. Tag: Unhandled exception after calling child form's Dispose(). Tag: 84042
  - 10
    - Changing DataViewManager.RowFilter has no effect On Feb 12 I posted a request for some help with the subject "Changing the DataViewManager.RowFilter has no effect". I attached some sample code written against Northwind demonstrating the problem. I may not have been logged in with my MSDN Email account so I am reposting my request under that account in the hopes that someone can take a quick look and point out the error of my ways. Thanks Tag: Unhandled exception after calling child form's Dispose(). Tag: 84040
  - 11
    - "Autohide menu bar" in Media Player I want to add the "Autohide menu bar" feature to my form like the Windows media player. (Menu bar is shown only when the mouse is over the non-client area. i.e. title bar, menu bar) However, seems the MouseMoved event is fired only when the mouse is moved over the visible area. Anyone knows how can i get informed when the mouse is moved over the invisible non-client area? Thanks! -- Regards, Hin Tag: Unhandled exception after calling child form's Dispose(). Tag: 84039
  - 12
    - Vertical scrolling for windowsforms in c# hi all, i need to create vertical scrollbar dynamically for the controls that are created dynamically in the form. (i'm not adding any controls to the panel). when the form exceeds(coz of dynamic controls creation) the default system coordinates, vertical scroll bar should be dynamically produced in the form. in this case i could produce the vscrollbar dynamically. but when i'm scrolling the form,the controls which are down couldn't be scrolled up. i'm doing it in this way, if(height >= 600) { vsb=new VScrollBar(); vsb.Dock=DockStyle.Right; vsb.Maximum = 600; vsb.LargeChange = 250; vsb.ValueChanged +=new EventHandler(vsb_ValueChanged); Controls.Add(vsb); } ... ... ... private void vsb_ValueChanged(object sender, EventArgs e) { this.Top = -vsb.Value; } any suggestion in this regard would be greatly appreciated. Thanks and Regards chris Tag: Unhandled exception after calling child form's Dispose(). Tag: 84036
  - 13
    - [ANN] February 15, 2005, "Debugging Visual Basic .NET Applications" chat Join members of the Visual Basic .NET and Debugging teams (Deeptanshu Verma, Jay Schmelzer, Lisa Feigenbaum, Bill Horst, Scott Nonnenberg, and Rekha Cuppala) to discuss debugging Visual Basic .NET applications with the Visual Studio .NET Debugger. Almost every program will need to be debugged sometime, so take this opportunity to chat with the experts about debugging. Date: February 15, 2005 1:00 - 2:00 P.M. Pacific time 4:00 - 5:00 P.M. Eastern time 21:00 - 22:00 GMT (For a list of the start time in several local time zones, please see http://www.timeanddate.com/worldclock/fixedtime.html?month=11&day=2&hour=13&min=0&sec=0&p1=234) Outlook Reminder: http://msdn.microsoft.com/chats/outlook_reminders/05_Feb15_DBUG_VBNET.ics Location (click the name of the chat to enter the chat room) http://msdn.microsoft.com/chats For more information about Visual Basic .NET, see http://msdn.microsoft.com/vbasic/ To see a list of upcoming chats or set a reminder for this chat, see http://msdn.microsoft.com/chats. For archives of previous chats, see http://msdn.microsoft.com/chats/recent.asp. Thanks! Jason Cooke Visual Basic Team ======== This posting is provided "AS IS" with no warranties, and confers no rights. You assume all risk for your use. (c) 2005 Microsoft Corporation. All rights reserved. Tag: Unhandled exception after calling child form's Dispose(). Tag: 84033
  - 14
    - label.visible does not work I'm developing a quite comlex form containing a user control in C# In the user control I'm trying to set a simple label to be visible: labelState.Visible = true; The debugger showns me, that the labelState.Visible is false before entering this line of code. But it is still false after this line of code!!! Can anyone please explain, how this can happen? I have double checked that I have not defined an event on this label that resets the value to false. Is there any posiible condition that does not allow to set a label's visibility to true? Regards Burkhard Mahr ------------------------- Label Initialization Code: this.labelState.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Right))); this.labelState.BackColor = System.Drawing.Color.Transparent; this.labelState.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0))); this.labelState.Location = new System.Drawing.Point(870, 4); this.labelState.Name = "labelState"; this.labelState.Size = new System.Drawing.Size(44, 16); this.labelState.TabIndex = 16; this.labelState.Text = "Status"; Tag: Unhandled exception after calling child form's Dispose(). Tag: 84027
  - 15
    - How to create an click event in a form automatic(C#) Hello Now i have try create an click event in a form,so i doubleclick the form,but the IDE create an form_load event automatic: private void Form2_Load(object sender, System.EventArgs e) { } but the code i need is: private void Form2_Click(object sender, System.EventArgs e) { } so i had write it by hand,but it not work,i find some books,and add some codes: this.Click += new System.EventHandler(this.Form2_Click); Haha,it work,but how can IDE create an click event automatic,not with handwrite? Tag: Unhandled exception after calling child form's Dispose(). Tag: 84023
  - 16
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Hello,

I have a main form (MainForm) which contains File->New menu item. On
clicking File->New menu item, i am displaying a form (ChildForm) which
contains a lot of controls and a lot of complex code. Everytime the
File->New menu item is clicked, a new instance of ChildForm is created and
shown as modal dialog with MainForm as owner. In the ChildForm's Dispose()
method, i have included code to remove all event handlers, cleanup the
controls etc. After call to ChildForm.ShowDialog(MainForm), i am calling the
ChildForm.Dispose() method explicitly, to release the window handles.

The problem here is I am getting an Unhandled Exception saying
"System.NullReferenceException: Object reference not set to an instance of
an object.
at System.Windows.Forms.ChildWindow.Callback(IntPtr hWnd, Int32 msg,
IntPtr wparam, IntPtr lparam)".

Please help me!

Thanks,
VijayakrishNa P.

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Re: Unhandled exception after calling child form's Dispose(). by Vijayakrishna

Vijayakrishna
Thu Feb 17 04:37:44 CST 2005

Sorry, I forgot to tell, I am getting the unhandled exception when i click
on the File->New Menu item.

"Vijayakrishna Pondala" <pvijkris@hotmail.com> wrote in message
news:OvaUkpNFFHA.2564@tk2msftngp13.phx.gbl...
> Hello,
>
> I have a main form (MainForm) which contains File->New menu item. On
> clicking File->New menu item, i am displaying a form (ChildForm) which
> contains a lot of controls and a lot of complex code. Everytime the
> File->New menu item is clicked, a new instance of ChildForm is created and
> shown as modal dialog with MainForm as owner. In the ChildForm's Dispose()
> method, i have included code to remove all event handlers, cleanup the
> controls etc. After call to ChildForm.ShowDialog(MainForm), i am calling
the
> ChildForm.Dispose() method explicitly, to release the window handles.
>
> The problem here is I am getting an Unhandled Exception saying
> "System.NullReferenceException: Object reference not set to an instance of
> an object.
> at System.Windows.Forms.ChildWindow.Callback(IntPtr hWnd, Int32 msg,
> IntPtr wparam, IntPtr lparam)".
>
> Please help me!
>
> Thanks,
> VijayakrishNa P.
>
>

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