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AsyncCompletedEventArgs.Error Property

Gets a value indicating which error occurred during an asynchronous operation.

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

member Error : Exception

Property Value

Type: System.Exception
An Exception instance, if an error occurred during an asynchronous operation; otherwise a null reference (Nothing in Visual Basic).

If an exception is raised during an asynchronous operation, the class will assign the exception to the Error property. The client application's event-handler delegate should check the Error property before accessing any properties in a class derived from AsyncCompletedEventArgs; otherwise, the property will raise a TargetInvocationException with its InnerException property holding a reference to Error.

The value of the Error property is a null reference (Nothing in Visual Basic) if the operation was canceled.

Notes to Inheritors

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

The following code example demonstrates 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.

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

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.
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