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AsyncCompletedEventArgs.Cancelled Property

Gets a value indicating whether an asynchronous operation has been canceled.

Namespace: System.ComponentModel
Assembly: System (in system.dll)

property bool Cancelled {
	bool get ();
/** @property */
public boolean get_Cancelled ()

public function get Cancelled () : boolean

Not applicable.

Property Value

true if the background operation has been canceled; otherwise false. The default is false.

When the Cancelled property is true, the asynchronous operation was interrupted.

The client application's event-handler delegate should check the Cancelled property before accessing any properties in a class derived from AsyncCompletedEventArgs; otherwise, the property will raise an InvalidOperationException if the asynchronous operation was interrupted.

Notes to Inheritors: If you provide read-only properties in a derived class, be sure to call the RaiseExceptionIfNecessary method. This prevents clients from accessing properties that are potentially not valid due to a failure in the asynchronous operation.

The following code example demonstrates the using an AsyncOperation to track the lifetime of asynchronous operations. This code example is part of a larger example provided for the System.ComponentModel.AsyncOperationManager class.

No code example is currently available or this language may not be supported.
import System.*;
import System.Collections.*;
import System.Collections.Specialized.*;
import System.ComponentModel.*;
import System.Data.*;
import System.Drawing.*;
import System.Threading.*;
import System.Windows.Forms.*;


    private void primeNumberCalculator1_CalculatePrimeCompleted(Object sender,
        CalculatePrimeCompletedEventArgs e)
        Guid guid = (Guid)e.get_UserState();
        if (e.get_Cancelled()) {
            String result = "Cancelled";
            ListViewItem lvi = UpdateListViewItem((Guid)e.get_UserState(),
            if (lvi != null) {
        else {
            if (e.get_Error() != null) {
                String result = "Error";
                ListViewItem lvi = UpdateListViewItem((Guid)e.get_UserState(),
                if (lvi != null) {
            else {
                boolean result = e.get_IsPrime();
                ListViewItem lvi = UpdateListViewItem((Guid)e.get_UserState(),
                    result, e.get_FirstDivisor());
                if (lvi != null) {
    } //primeNumberCalculator1_CalculatePrimeCompleted

Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0

XNA Framework

Supported in: 1.0