ThreadExceptionEventArgs Class

Definition

public ref class ThreadExceptionEventArgs : EventArgs

public class ThreadExceptionEventArgs : EventArgs

type ThreadExceptionEventArgs = class
    inherit EventArgs

Public Class ThreadExceptionEventArgs
Inherits EventArgs

Inheritance

Object

EventArgs

ThreadExceptionEventArgs

Derived

Microsoft.VisualBasic.ApplicationServices.UnhandledExceptionEventArgs

Examples

The following example allows you to raise a ThreadException event by clicking button1 on a form. The example creates two classes. The ErrorHandler class creates the form and the button that raises the event. The CustomExceptionHandler class provides the methods to handle the exception.

In Main in the ErrorHandler class, the code creates a new instance of the exception handling class, that is, an instance of the CustomExceptionHandler. Then the instance is added to the event, and the application is run.

In the OnThreadException method in the CustomExceptionHandler class, the example uses a try...catch...finally statement to process the exception. The ShowThreadExceptionDialog method creates the message to display, and displays it in a message box.

using System;
using System.Threading;
using System.Windows.Forms;

// Create a form with a button that, when clicked, throws an exception.
 public class ErrorForm : System.Windows.Forms.Form
 {
    internal Button button1;

    public ErrorForm() : base()
    {
       // Add the button to the form.
       this.button1 = new System.Windows.Forms.Button();
       this.SuspendLayout();
       this.button1.Location = new System.Drawing.Point(100, 43);
       this.button1.Size = new System.Drawing.Size(75, 23);
       this.button1.Text = "Click!";
       this.Controls.Add(this.button1);
       this.button1.Click += new EventHandler(this.button1_Click);

       this.Text = "ThreadException";
       this.ResumeLayout(false);
    }

    // Throw an exception when the button is clicked.
    private void button1_Click(object sender, System.EventArgs e)
    {
       throw new ArgumentException("The parameter was invalid");
    }

    public static void Main()
    {
       // Add the event handler.
       Application.ThreadException += new ThreadExceptionEventHandler(CustomExceptionHandler.OnThreadException);

       // Start the example.
       Application.Run(new ErrorForm());
    }
 }

 // Create a class to handle the exception event.
 internal class CustomExceptionHandler
 {
     // Handle the exception event
    public static void OnThreadException(object sender, ThreadExceptionEventArgs t)
    {
       DialogResult result = ShowThreadExceptionDialog(t.Exception);

       // Exit the program when the user clicks Abort.
       if (result == DialogResult.Abort)
          Application.Exit();
    }

    // Create and display the error message.
    private static DialogResult ShowThreadExceptionDialog(Exception e)
    {
       string errorMsg = "An error occurred.  Please contact the adminstrator " +
            "with the following information:\n\n";
       errorMsg += string.Format("Exception Type: {0}\n\n", e.GetType().Name);
       errorMsg += "\n\nStack Trace:\n" + e.StackTrace;
       return MessageBox.Show(errorMsg, "Application Error",
            MessageBoxButtons.AbortRetryIgnore, MessageBoxIcon.Stop);
    }
 }

Imports System.Threading
Imports System.Windows.Forms

' Create a form with a button that, when clicked, throws an exception.
Public Class ErrorForm : Inherits Form
    Friend WithEvents button1 As Button

    Public Sub New()
       ' Add the button to the form.
      Me.button1 = New System.Windows.Forms.Button()
      Me.SuspendLayout()
      Me.button1.Location = New System.Drawing.Point(100, 43)
      Me.button1.Size = New System.Drawing.Size(75, 23)
      Me.button1.Text = "Click!"
      Me.Controls.Add(Me.button1)

      Me.Text = "ThreadException"
      Me.ResumeLayout(False)
   End Sub

    ' Throw an exception when the button is clicked.
    Private Sub button1_Click(sender As Object, e As System.EventArgs) _
                Handles button1.Click
        Throw New ArgumentException("The parameter was invalid.")
    End Sub
    
    Public Shared Sub Main()
        ' Add the event handler.
        AddHandler Application.ThreadException,
                   AddressOf CustomExceptionHandler.OnThreadException
        
        ' Start the example.
        Application.Run(New ErrorForm())
    End Sub
End Class

' Create a class to handle the exception event.
Friend Class CustomExceptionHandler
    'Handle the exception event.
    Public Shared Sub OnThreadException(sender As Object, t As ThreadExceptionEventArgs)
        Dim result As DialogResult = ShowThreadExceptionDialog(t.Exception)

        ' Exit the program when the user clicks Abort.
        If result = DialogResult.Abort Then
            Application.Exit()
        End If
    End Sub
     
    ' Create and display the error message.
    Private Shared Function ShowThreadExceptionDialog(e As Exception) As DialogResult
        Dim errorMsg As String = "An error occurred.  Please contact the " &
            "adminstrator with the following information:" &
            vbCrLf & vbCrLf
        errorMsg &= "Exception Type: " & e.GetType().Name & vbCrLf & vbCrLf
        errorMsg &= e.Message & vbCrLf & vbCrLf
        errorMsg &= "Stack Trace: " & vbCrLf & e.StackTrace

        Return MessageBox.Show(errorMsg, "Application Error",
               MessageBoxButtons.AbortRetryIgnore, MessageBoxIcon.Stop)
    End Function
End Class

Remarks

A ThreadExceptionEventArgs is created by a thread when an unhandled exception occurs. ThreadExceptionEventArgs contains the Exception that occurred.

Constructors

Properties

Methods

Applies to

See also

• Thread
• ThreadStart
• ThreadExceptionEventHandler