'宣言 Property Completed As C1.Document.AsyncActionWithProgressCompletedHandler(Of TProgress)
'使用法 Dim instance As IAsyncActionWithProgress(Of TProgress) Dim value As C1.Document.AsyncActionWithProgressCompletedHandler(Of TProgress) instance.Completed = value value = instance.Completed
C1.Document.AsyncActionWithProgressCompletedHandler<TProgress> Completed {get; set;}