Gets a value indicating which error occurred during an asynchronous operation.
Assembly: System (in System.dll)
If an exception is raised during an asynchronous operation, the class will assign the exception to the property. The client application's event-handler delegate should check the 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 .
The value of the 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.
Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.