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ThreadExceptionEventArgs Class

Provides data for the ThreadException event.

Namespace:  System.Threading
Assembly:  System (in System.dll)

public class ThreadExceptionEventArgs : EventArgs

The ThreadExceptionEventArgs type exposes the following members.

Public methodThreadExceptionEventArgsInitializes a new instance of the ThreadExceptionEventArgs class.

Public propertyExceptionGets the Exception that occurred.

Public methodEquals(Object)Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodGetHashCodeServes as a hash function for a particular type. (Inherited from Object.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)

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

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.

// Creates a class to throw the error.
 public class ErrorHandler : System.Windows.Forms.Form {

    // Inserts code to create a form with a button.

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

    public static void Main(string[] args) {
       // Creates an instance of the methods that will handle the exception.
       CustomExceptionHandler eh = new CustomExceptionHandler();

       // Adds the event handler to to the event.
       Application.ThreadException += new ThreadExceptionEventHandler(eh.OnThreadException);

       // Runs the application.
       Application.Run(new ErrorHandler());

 // Creates a class to handle the exception event.
 internal class CustomExceptionHandler {

    //Handles the exception event
    public void OnThreadException(object sender, ThreadExceptionEventArgs t) 
       DialogResult result = DialogResult.Cancel;
       try {
          result = this.ShowThreadExceptionDialog(t.Exception);
       catch {
          try {
             MessageBox.Show("Fatal Error", "Fatal Error", 
                MessageBoxButtons.AbortRetryIgnore, MessageBoxIcon.Stop);
          finally {

       // Exits the program when the user clicks Abort.
       if (result == DialogResult.Abort) 

    // Creates the error message and display it.
    private DialogResult ShowThreadExceptionDialog(Exception e) {
       string errorMsg = "An error occurred please contact the adminstrator " +
            "with the following information:\n\n";
       errorMsg = errorMsg + e.Message + "\n\nStack Trace:\n" + e.StackTrace;
       return MessageBox.Show(errorMsg, "Application Error", 
            MessageBoxButtons.AbortRetryIgnore, MessageBoxIcon.Stop);

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.