Task.WaitAll Method (Task, CancellationToken)
Waits for all of the provided cancellable Task objects to complete execution.
Assembly: mscorlib (in mscorlib.dll)
The cancellationToken was canceled.
The tasks argument is null.
At least one of the Task instances was canceled -or- an exception was thrown during the execution of at least one of the Task instances. If a task was canceled, the AggregateException contains an OperationCanceledException in its InnerExceptions collection.
The tasks argument contains a null element.
One or more of the Task objects in tasks has been disposed.
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)