Problem displaying a messageBox

Question

Hi I'm working on a WinForm application with .NET CF 2.0 and I have a background running thread that needs to notify the user about various events. The problem is that everytime I want to notify the user with a MessageBox about an event the application exits once the messagebox is displayed...I get the following message in the output window: The thread 0x2eda2a2 has exited with code 0 (0x0). However if I display the message in a label of my form everything works well...here is the code I use: public void DisplayMessage(string message) { if (InvokeRequired) { DisplayMessageDelegate displayMessageDelegate = new DisplayMessageDelegate(DisplayMessage); this.Invoke(displayMessageDelegate new object[] { message }); } else { this.labelStatus.Text = message; // Works well MessageBox.Show(message Info MessageBoxButtons.OK MessageBoxIcon.Exclamation MessageBoxDefaultButton.Button1); // Application exits when called } } Thanks in advance! alex

Mike Gold · Answer

I just tried it with your code and it seems to work fine. Here is the code I called in my Form to ensure it was being called from a separate thread. Could some other part of your program be causing an exit? I would turn on exception handling under Exceptions in the Debug Menu and check the CLR Exceptions : private void Form1_Load ( object sender  EventArgs e ) { // TODO: This line of code loads data into the 'fPNWINDDataSet.Customers' table. You can move or remove it as needed. Thread oMessage = new Thread ( new ThreadStart ( ShowMessage )); oMessage . Start (); } private void ShowMessage () { DisplayMessage ( testing ); } private delegate void DisplayMessageDelegate ( string msg ); public void DisplayMessage ( string message ) { if ( InvokeRequired ) { DisplayMessageDelegate displayMessageDelegate = new DisplayMessageDelegate ( DisplayMessage ); this . Invoke ( displayMessageDelegate  new object [] { message }); } else { // this.labelStatus.Text = message; // Works well MessageBox . Show ( message  Info  MessageBoxButtons . OK  MessageBoxIcon . Exclamation  MessageBoxDefaultButton . Button1 ); // Application exits when called } }

Mike Gold · Answer

I would try as an experiment to create a message box from a Windows Form and calling ShowDialog instead of using MessageBox. See if you still get the same problem of exiting. You can also try my scrollable message box and see if it causes an exit.

Alex · Answer

My delegate used to call a different method but I've seen in the Safe Simple Multithreading in Windows Form tutorial [http://msdn2.microsoft.com/en-us/library/ms951089.aspx] that their delegate was invoking back the same method which avoids creating 2 methods doing almost the same thing. Thanks!

Mike Gold · Answer

try putting the method that you are delegating to in a separate method. Looks like you are invoking back to the same method you are in which I suspect is dangerous.