Handle global exceptions in VB

问题

Hello I have this project experiencing some problems with what is supposed to be my codes for the "problem" handler.

Public Event UnhandledException As UnhandledExceptionEventHandler

 Private Sub form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
            Dim currentDomain As AppDomain = AppDomain.CurrentDomain

            AddHandler currentDomain.UnhandledException, AddressOf MyHandler
        End Sub

    Sub MyHandler(ByVal sender As Object, ByVal args As UnhandledExceptionEventArgs)
            Dim e As Exception = DirectCast(args.ExceptionObject, Exception)

            Using sw As New StreamWriter(File.Open(myFilePath, FileMode.Append))
                sw.WriteLine(Date.now & e.toString)
            End Using

            MessageBox.Show("An unexcpected error occured. Application will be terminated.")
            Application.Exit()
        End Sub

        Private Sub button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles button1.Click
            Throw New Exception("Dummy Error")
        End Sub

I'm trying to globally catch all exceptions and create logfile during runtime, which works fine in the debugger(exception handling and textfile writing) but cannot catch any unhandled exceptions after I build it in the setup project and Installed into a machine. What am I missing? Do I need to include additional components to my setup project? Help would be greatly appreciated

回答1:

There is already a way to handle exceptions for the entire application. Embedding the handler in a form means they would only be caught and logged if and while that form was open.

1. Go to Project -> Properties -> Application and click the "View Application Events" button at/near the bottom.

2. This will open ApplicationEvents.vb.

3. Select (MyApplicationEvents) in the left menu; and UnhandledException in the right. This opens an otherwise typical event handler to which you can add code:

   Private Sub MyApplication_UnhandledException(sender As Object,
                                                e As ApplicationServices.UnhandledExceptionEventArgs) Handles Me.UnhandledException
   
       Dim myFilePath As String = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments),
                                               "badjuju.log")
   
       Using sw As New StreamWriter(File.Open(myFilePath, FileMode.Append))
           sw.WriteLine(DateTime.Now)
           sw.WriteLine(e.Exception.Message)
       End Using
   
       MessageBox.Show("An unexcpected error occured. Application will be terminated.")
       End
   
   End Sub
   

This will not catch exceptions while the IDE is running because VS catches them first so you can see them and fix them.

来源：https://stackoverflow.com/questions/30488132/handle-global-exceptions-in-vb