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Parallel.For Method (Int32, Int32, Action<Int32>)

Executes a for (For in Visual Basic) loop in which iterations may run in parallel.

Namespace:  System.Threading.Tasks
Assembly:  mscorlib (in mscorlib.dll)

public static ParallelLoopResult For(
	int fromInclusive,
	int toExclusive,
	Action<int> body


Type: System.Int32
The start index, inclusive.
Type: System.Int32
The end index, exclusive.
Type: System.Action<Int32>
The delegate that is invoked once per iteration.

Return Value

Type: System.Threading.Tasks.ParallelLoopResult
A structure that contains information about which portion of the loop completed.


The body argument is null.


The exception that contains all the individual exceptions thrown on all threads.

The body delegate is invoked once for each value in the iteration range (fromInclusive, toExclusive). It is provided with the iteration count (Int32) as a parameter.

If fromInclusive is greater than or equal to toExclusive, the method returns immediately without performing any iterations.

.NET Framework

Supported in: 4

.NET Framework Client Profile

Supported in: 4

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.