Articolo
11/18/2011

ApplicationUnhandledExceptionEventArgs.Handled Property

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Gets or sets a value that indicates whether the exception is handled.

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

Syntax

'Declaration
Public Property Handled As Boolean

public bool Handled { get; set; }

Property Value

Type: System.Boolean
true to mark the exception as handled, which indicates that Silverlight should not process it further; otherwise, false.

Remarks

An unhandled exception, where Handled remains false upon exiting the UnhandledException handler, will be passed on to the unmanaged Silverlight event reporting mechanism, where applications can process it as an error through any registered OnError (Silverlight Plug-in Object) handler.

Examples

The following example shows how to handle and use the UnhandledException event.

Imports System.IO

Partial Public Class App
    Inherits Application

    Public Sub New()
        InitializeComponent()
    End Sub

    Private Sub Application_Startup(ByVal o As Object, _
        ByVal e As StartupEventArgs) Handles Me.Startup

        Me.RootVisual = New Page()

    End Sub

    Private Sub Application_UnhandledException(ByVal sender As Object, _
        ByVal e As ApplicationUnhandledExceptionEventArgs) Handles Me.UnhandledException

        If TypeOf e.ExceptionObject Is FileNotFoundException Then
            ' Inform the user 

            ' Recover from the error 
            e.Handled = True
            Return
        End If

        ' Exception is unrecoverable so stop the application and allow the 
        ' Silverlight plug-in control to detect and process the exception. 

    End Sub

End Class

using System.IO; // FileNotFoundException
using System.Windows; // Application, StartupEventArgs, ApplicationUnhandledExceptionEventArgs

namespace SilverlightApplication
{
    public partial class App : Application
    {
        public App()
        {
            this.Startup += this.Application_Startup;
            this.UnhandledException += this.Application_UnhandledException;

            InitializeComponent();
        }

        private void Application_Startup(object sender, StartupEventArgs e)
        {
            this.RootVisual = new Page();
        }

        private void Application_UnhandledException(object sender, 
            ApplicationUnhandledExceptionEventArgs e)
        {
            if (e.ExceptionObject is FileNotFoundException)
            {
                // Inform the user

                // Recover from the error
                e.Handled = true;
                return;
            }

            // Exception is unrecoverable so stop the application and allow the 
            // Silverlight plug-in control to detect and process the exception.
        }
    }
}

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

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