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.