Create a "catch all" Exception handler

[crptcblade]

This will catch any exception that you do not explicitly handle. Not only can you gather information about the state of the application when the exception is thrown, but it also gives you a chance to shut down the app cleanly.

Imports System.Threading
 
Public Class frmMain
    Inherits System.Windows.Forms.Form
 
    '//Windows Form Designer generated code
 
    Public Shared Sub Main()
        Dim frm As New frmMain
 
        'Install a ThreadException Handler
        AddHandler Application.ThreadException, _
                   New ThreadExceptionEventHandler(AddressOf frm.GlobalErrorProc)
 
        'Run the main form
        Application.Run(frm)
 
    End Sub
 
    Public Sub GlobalErrorProc(ByVal sender As Object, _
                               ByVal args As ThreadExceptionEventArgs)
 
        'Inform the user of the exception, and allow the application to close nicely
        MessageBox.Show("An unhandled exception has occured: " & args.Exception.Message, _
                        "Unhandled Exception", MessageBoxButtons.OK, MessageBoxIcon.Error)
        Me.Close()
        Application.Exit()
 
        'You could also write the stack trace out to a file or something at this for
        'debugging purposes, or gather any other state info that you want
 
    End Sub
 
    Private Sub Button1_Click(ByVal sender As Object, _
                              ByVal e As System.EventArgs) Handles Button1.Click
        'Just to test it out, throw an exception
        Throw New Exception("This is a test")
    End Sub
 
End Class

[Codehammer]

I Thought dim ex as Exception caught Everything!!

Worked Fine all These years.

[tr333]

I Thought dim ex as Exception caught Everything!!

Worked Fine all These years.

this example calls the GlobalErrorProc sub whenever an error occurs, so you dont have to have many try/catch statements.

[dee-u]

How about adding a feature like "Abort,Retry,Ignore"?

[MetalKid]

If this exception catches an error, it is already too late to try to continue on with any code, as there were no try/catches down below. Really, you should use try/catches where you can and use this handler for situations you didn't forsee crashing (as a safety net).

[OMITT3D]

It didn't work for me :'( it just threw the exception no msgbox no nothing =\

[Kasracer]

It's best to use Sub Main to launch your application and put that in a Try and Catch statement. That way, if an error occurs somewhere in your program you're guarenteed to catch it and do whatever you want with it.