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Parallel Class

An activity that executes all child activities simultaneously and asynchronously.

Namespace:  System.Activities.Statements
Assembly:  System.Activities (in System.Activities.dll)

[ContentPropertyAttribute("Branches")]
public sealed class Parallel : NativeActivity

The Parallel type exposes the following members.

  NameDescription
Public methodParallelCreates a new instance of the Parallel activity.
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  NameDescription
Public propertyBranchesThe child elements to be executed in parallel.
Protected propertyCacheIdGets the identifier of the cache that is unique within the scope of the workflow definition. (Inherited from Activity.)
Public propertyCompletionConditionEvaluates after any branch completes.
Public propertyDisplayNameGets or sets an optional friendly name that is used for debugging, validation, exception handling, and tracking. (Inherited from Activity.)
Public propertyIdGets an identifier that is unique in the scope of the workflow definition. (Inherited from Activity.)
Protected propertyImplementationVersionGets or sets the implementation version of the activity. (Inherited from NativeActivity.)
Public propertyVariablesThe collection of contained variables.
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  NameDescription
Public methodEquals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Public methodGetHashCodeServes as the default hash function. (Inherited from Object.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodShouldSerializeDisplayNameIndicates whether the DisplayName property should be serialized. (Inherited from Activity.)
Public methodToStringReturns a String that contains the Id and DisplayName of the Activity. (Inherited from Activity.)
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A Parallel activity operates by simultaneously scheduling each Activity in its Branches collection at the start. It completes when all of its Branches complete or when its CompletionCondition property evaluates to true. While all the Activity objects run asynchronously, they do not execute on separate threads, so each successive activity only executes when the previously scheduled activity completes or goes idle. If none of the child activities of this activity go idle, this activity execute in the same way that a Sequence activity does.

The following code sample demonstrates creating a Parallel activity. This example is from the Cancellation Handler on Compensable Activity sample.

return new Parallel
{
    // Timeout from branch causes other branch to cancel.
    CompletionCondition = true,

    Branches =
    {
        // Delay Branch 
        new Sequence
        {
            Activities =
            {
                new WriteLine { Text = "Branch1: Body is about to Delay 2secs transferring execution to Branch2" },
                new Delay
                {
                    Duration = TimeSpan.FromSeconds(2)
                },
                new WriteLine { Text = "Branch1: Body is about to complete causing Branch2 to cancel.." },
            }
        },

.NET Framework

Supported in: 4.6, 4.5, 4

.NET Framework Client Profile

Supported in: 4

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
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