ParallelForEach<T> Class

Definition

Namespace:

System.Activities.Statements

Assembly:

System.Activities.dll

Enumerates the elements of a collection and executes an embedded statement for each element of the collection in parallel.

generic <typename T>
public ref class ParallelForEach sealed : System::Activities::NativeActivity

[System.Windows.Markup.ContentProperty("Body")]
public sealed class ParallelForEach<T> : System.Activities.NativeActivity

[<System.Windows.Markup.ContentProperty("Body")>]
type ParallelForEach<'T> = class
    inherit NativeActivity

Public NotInheritable Class ParallelForEach(Of T)
Inherits NativeActivity

Type Parameters

T

The type of the values provided in the Values collection.

Inheritance

Object

Activity

NativeActivity

ParallelForEach<T>

Attributes

ContentPropertyAttribute

Examples

The following code sample demonstrates creating a ParallelForEach<T> activity. This example is from the Corporate Purchase Process sample.

// invite all vendors and wait for their proposals
new ParallelForEach<Vendor>
{
    DisplayName = "Get vendor proposals",
    Values = new InArgument<IEnumerable<Vendor>>(ctx =>this.Rfp.Get(ctx).InvitedVendors),
    Body = new ActivityAction<Vendor>()
    {
        Argument = iterationVariableVendor,
        Handler = new Sequence
        {
            Variables = { tmpValue },
            Activities =
            {
                // waits for a vendor proposal (creates a bookmark for a vendor)
                new WaitForVendorProposal
                {
                    VendorId = new LambdaValue<int>(ctx =>iterationVariableVendor.Get(ctx).Id) ,
                    Result = new OutArgument<double>(tmpValue)
                },

                // after the vendor proposal is received, it is registered in the Request for Proposals
                new InvokeMethod
                {
                    TargetObject = new InArgument<RequestForProposal>(ctx =>this.Rfp.Get(ctx)),
                    MethodName = "RegisterProposal",
                    Parameters =
                    {
                        new InArgument<Vendor>(iterationVariableVendor),
                        new InArgument<double>(tmpValue)
                    }
                },
            }
        }
    }
},

Remarks

The embedded statements are scheduled together and run asynchronously, but unless the scheduled activities themselves are asynchronous (such as messaging activities, InvokeMethod, or activities that derive from AsyncCodeActivity), they do not run on separate threads, so each successive activity will only execute when the previously scheduled activity completes or goes idle. If none of the child activities of this activity are asynchronous or go idle, this activity execute in the same way that a ForEach<T> activity does.

Constructors

ParallelForEach<T>()

Creates a new instance of the ParallelForEach<T> class.

Properties

Body	The ActivityAction that is executed once for every value contained in the Values collection.
CacheId	Gets the identifier of the cache that is unique within the scope of the workflow definition. (Inherited from Activity)
CanInduceIdle	Gets or sets a value that indicates whether the activity can cause the workflow to become idle. (Inherited from NativeActivity)
CompletionCondition	Evaluated after each iteration completes.
Constraints	Gets a collection of Constraint activities that can be configured to provide validation for the Activity. (Inherited from Activity)
DisplayName	Gets or sets an optional friendly name that is used for debugging, validation, exception handling, and tracking. (Inherited from Activity)
Id	Gets an identifier that is unique in the scope of the workflow definition. (Inherited from Activity)
Implementation	The execution logic of the activity. (Inherited from NativeActivity)
ImplementationVersion	Gets or sets the implementation version of the activity. (Inherited from NativeActivity)
Values	The collection of values used as parameters for each iteration of the activity contained in the Body.

Methods

Abort(NativeActivityAbortContext)	When implemented in a derived class, takes actions in response to the activity being aborted. (Inherited from NativeActivity)
CacheMetadata(ActivityMetadata)	Not implemented. Use the CacheMetadata(NativeActivityMetadata) method instead. (Inherited from NativeActivity)
CacheMetadata(NativeActivityMetadata)	Creates and validates a description of the activity's arguments, variables, child activities, and activity delegates. (Inherited from NativeActivity)
Cancel(NativeActivityContext)	When implemented in a derived class, runs logic to cause graceful early completion of the activity. (Inherited from NativeActivity)
Equals(Object)	Determines whether the specified object is equal to the current object. (Inherited from Object)
Execute(NativeActivityContext)	When implemented in a derived class, runs the activity's execution logic. (Inherited from NativeActivity)
GetHashCode()	Serves as the default hash function. (Inherited from Object)
GetType()	Gets the Type of the current instance. (Inherited from Object)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
OnCreateDynamicUpdateMap(NativeActivityUpdateMapMetadata, Activity)	Raises an event when creating a map for the dynamic update. (Inherited from NativeActivity)
OnCreateDynamicUpdateMap(UpdateMapMetadata, Activity)	Raises an event when creating a map for the dynamic update. (Inherited from NativeActivity)
ShouldSerializeDisplayName()	Indicates whether the DisplayName property should be serialized. (Inherited from Activity)
ToString()	Returns a String that contains the Id and DisplayName of the Activity. (Inherited from Activity)
UpdateInstance(NativeActivityUpdateContext)	Updates the instance of NativeActivity. (Inherited from NativeActivity)