Task.WaitAll Method (Task, Int32)
Waits for all of the provided Task objects to complete execution within a specified number of milliseconds.
Assemblies: System.Threading.Tasks (in System.Threading.Tasks.dll)
mscorlib (in mscorlib.dll)
One or more of the Task objects in tasks has been disposed.
The tasks argument is a null reference (Nothing in Visual Basic).
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.
millisecondsTimeout is a negative number other than -1, which represents an infinite time-out.
The tasks argument contains a null element.
.NET FrameworkSupported in: 4.6, 4.5, 4
.NET Framework Client ProfileSupported in: 4
Portable Class LibrarySupported in: Portable Class Library
.NET for Windows Store appsSupported in: Windows 8
Supported in: Windows Phone 8.1
Supported in: Windows Phone Silverlight 8.1
Supported in: Windows Phone Silverlight 8
Windows Phone 8.1, Windows Phone 8, 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)