My.Application.UnhandledException Event 

Occurs when the application encounters an unhandled exception.

' Usage
Public Sub Me_UnhandledException( _
   ByVal sender As Object, _
   ByVal e As UnhandledExceptionEventArgs _
) Handles Me.UnhandledException
End Sub
' Declaration
Public Event UnhandledException( _
   ByVal sender As Object, _
   ByVal e As UnhandledExceptionEventArgs _
)

Parameters

• sender
  The Object that raised the event.

• e
  An UnhandledExceptionEventArgs object that contains the unhandled exception and additional information.

Remarks

An application raises the UnhandledException event when it encounters an unhandled exception. This event is part of the Visual Basic Application model. For more information, see Overview of the Visual Basic Application Model.

You can use the Exception property of the e parameter to access the unhandled exception that caused this event.

You can use the ExitApplication property of the e parameter to control whether the application exits. By default, ExitApplication is True, so the application exits after completing the UnhandledException event handler. You can set the value to True in the UnhandledException event handler to keep the application running, and have it return to a waiting state.

The code for the UnhandledException event handler is stored in the ApplicationEvents.vb file, which is hidden by default.

To access the Code Editor window for application events:

1. With a project selected in Solution Explorer, click Properties on the Project menu.

2. Click the Application tab.

3. Click the View Application Events button to open the Code Editor.

For more information, see How to: Handle Application Events (Visual Basic).

Tasks

The following table lists examples of tasks involving the My.Application.UnhandledException event.

Example

This example uses the My.Application.UnhandledException event to log any unhandled exceptions.

Private Sub MyApplication_UnhandledException( _
    ByVal sender As Object, _
    ByVal e As Microsoft.VisualBasic.ApplicationServices.UnhandledExceptionEventArgs _
) Handles Me.UnhandledException
    My.Application.Log.WriteException(e.Exception, _
        TraceEventType.Critical, _
        "Unhandled Exception.")
End Sub

You must enter the code in the Code Editor window for application events. To access this window, follow the procedure found in this topic's Remarks section. For more information, see How to: Handle Application Events (Visual Basic).

Because the UnhandledException event is not raised when a debugger is attached to the application, you need to run this example outside of the Visual Studio Integrated Development Environment,

Requirements

Namespace: Microsoft.VisualBasic.ApplicationServices

Class: WindowsFormsApplicationBase

Assembly: Visual Basic Runtime Library (in Microsoft.VisualBasic.dll)

Availability by Project Type

Permissions

The following permissions may be necessary:

For more information, see Code Access Security and Requesting Permissions.

See Also

Reference

My.Application Object
Microsoft.VisualBasic.ApplicationServices.UnhandledExceptionEventArgs

Concepts

Overview of the Visual Basic Application Model