ParallelActivity Class



This API is now obsolete.

Runs a set of child activities at the same time. This class cannot be inherited.

public ref class ParallelActivity sealed : System::Workflow::ComponentModel::CompositeActivity, System::Workflow::ComponentModel::IActivityEventListener<System::Workflow::ComponentModel::ActivityExecutionStatusChangedEventArgs ^>
[System.Drawing.ToolboxBitmap(typeof(System.Workflow.Activities.ParallelActivity), "Resources.Parallel.png")]
[System.Obsolete("The System.Workflow.* types are deprecated.  Instead, please use the new types from System.Activities.*")]
public sealed class ParallelActivity : System.Workflow.ComponentModel.CompositeActivity, System.Workflow.ComponentModel.IActivityEventListener<System.Workflow.ComponentModel.ActivityExecutionStatusChangedEventArgs>
type ParallelActivity = class
    inherit CompositeActivity
    interface IActivityEventListener<ActivityExecutionStatusChangedEventArgs>
Public NotInheritable Class ParallelActivity
Inherits CompositeActivity
Implements IActivityEventListener(Of ActivityExecutionStatusChangedEventArgs)


The following code example shows how to create a new instance of the ParallelActivity class, add the ParallelActivity class to the WhileActivity class, and add two SequenceActivity classes to the ParallelActivity class. This code example is part of the WhileAndParallel SDK sample from the WhileAndParallelWorkflow.Designer.cs file. For more information, see Using While and Parallel.

workflowRuntime.WorkflowLoaded += OnWorkflowLoad;
AddHandler currentWorkflowRuntime.WorkflowLoaded, AddressOf OnWorkflowLoaded



This material discusses types and namespaces that are obsolete. For more information, see Deprecated Types in Windows Workflow Foundation 4.5.

The order in which child activities are run is non-deterministic.

The ParallelActivity is a CompositeActivity, which means the ParallelActivity can contain other activities. The SequenceActivity activity is the only activity that can be the child of a ParallelActivity.

Only one activity can run at a time.

The ParallelActivity only finishes when all children are complete.

The ParallelActivity is especially useful when there are one or more blocking activities, such as the DelayActivity activity, in one or more of the branches. In this scenario, the ParallelActivity actually switches to a different branch when the DelayActivity is blocked. If there are no blocking activities in any one of the ParallelActivity branches then the activity uses a non-deterministic sequence.



Initializes a new instance of the ParallelActivity class.


Initializes a new instance of the ParallelActivity class using the name of the activity.



Gets the object representing the collection, ActivityCollection, of all child activities.

(Inherited from CompositeActivity)

Gets or sets a value which controls whether the individual activities within Activities can be modified.

(Inherited from CompositeActivity)

Gets or sets the user-defined description of the Activity.

(Inherited from Activity)

Gets the value that indicates whether this instance is in design or run-time mode.

(Inherited from DependencyObject)

Gets or sets a value that indicates whether this instance is enabled for execution and validation.

(Inherited from Activity)

Gets the read-only collection that represents the subset of Activities that are enabled.

(Inherited from CompositeActivity)

Gets the ActivityExecutionResult of the last attempt to run this instance.

(Inherited from Activity)

Gets the current ActivityExecutionStatus of this instance.

(Inherited from Activity)

Gets information about whether the activity is executing within the default ActivityExecutionContext of the workflow instance.

(Inherited from Activity)

Gets or sets the name of this instance. This name must conform to the variable naming convention of the programming language that is being used in the Workflow project.

(Inherited from Activity)

Gets the CompositeActivity that contains this Activity.

(Inherited from Activity)

Gets the parent DependencyObject in the DependencyObject graph.

(Inherited from DependencyObject)

Gets the qualified name of the activity. Qualified activity names are always unique in a workflow instance.

(Inherited from Activity)

Gets or sets a reference to the Site component of the DependencyObject.

(Inherited from DependencyObject)

Gets an IDictionary that associates custom data with this class instance.

(Inherited from DependencyObject)

Gets the Guid associated with the instance.

(Inherited from Activity)


AddHandler(DependencyProperty, Object)

Adds a handler for an event of a DependencyObject.

(Inherited from DependencyObject)

Applies the WorkflowChanges manifest in the parameter to this instance.

(Inherited from CompositeActivity)

Called by the workflow runtime to cancel execution of an activity that is currently executing.

(Inherited from Activity)

Creates a deep copy of the Activity.

(Inherited from Activity)

Releases all the resources used by the DependencyObject.

(Inherited from DependencyObject)

Calls Dispose(Boolean) on this instance, and optionally calls Dispose() on all child activities of this instance.

(Inherited from CompositeActivity)

Determines whether the specified object is equal to the current object.

(Inherited from Object)

Called by the workflow runtime to execute an activity.

(Inherited from Activity)

Returns the instance of the Activity whose name is requested from the set of all activities running under the root activity of this instance, which is within the workflow.

(Inherited from Activity)
GetActivityByName(String, Boolean)

Returns the instance of the Activity whose name is requested from the set of all activities under the root the Activity of this instance if the second parameter is false and under the current Activity if the second parameter is true.

(Inherited from Activity)

Provides access to the ActivityBind associated with the specific DependencyProperty.

(Inherited from DependencyObject)
GetBoundValue(ActivityBind, Type)

Retrieves the Object that is the subject of an ActivityBind.

(Inherited from DependencyObject)

Returns an array that contains all of the currently executing instances of the specified activity.

(Inherited from CompositeActivity)

Serves as the default hash function.

(Inherited from Object)

Gets an array that contains the delegates for the specified DependencyProperty.

(Inherited from DependencyObject)

Gets the Type of the current instance.

(Inherited from Object)

Provides access to the value of the designated DependencyProperty.

(Inherited from DependencyObject)

Provides access to the bound object of a DependencyProperty and bypasses the GetValue(DependencyProperty) override.

(Inherited from DependencyObject)
HandleFault(ActivityExecutionContext, Exception)

Called when an exception is raised within the context of the execution of this instance.

(Inherited from CompositeActivity)

Initializes all appropriate child activities of this instance and the specified IServiceProvider.

(Inherited from CompositeActivity)

Performs initialization on dependency properties when overridden in a derived class.

(Inherited from DependencyObject)
Invoke<T>(EventHandler<T>, T)

Subscribes an EventHandler and invokes that delegate.

(Inherited from Activity)
Invoke<T>(IActivityEventListener<T>, T)

Subscribes an IActivityEventListener<T> and invokes that delegate.

(Inherited from Activity)

Indicates whether the value of a DependencyProperty is set as a binding. See SetBinding(DependencyProperty, ActivityBind).

(Inherited from DependencyObject)

Creates a shallow copy of the current Object.

(Inherited from Object)

Determines whether the metaproperties of this DependencyObject equals the metaproperties of the parameterized DependencyObject.

(Inherited from DependencyObject)
OnActivityChangeAdd(ActivityExecutionContext, Activity)

Calls when an activity is added.

(Inherited from CompositeActivity)
OnActivityChangeRemove(ActivityExecutionContext, Activity)

Called when an activity is removed.

(Inherited from CompositeActivity)

Called by the workflow runtime engine every time the ActivityExecutionContext for this activity is loaded.

(Inherited from CompositeActivity)

Called by the workflow runtime engine every time the ActivityExecutionContext for this activity is unloaded.

(Inherited from CompositeActivity)

Called by the workflow runtime as part of the activity's transition to the closed state.

(Inherited from Activity)

Performs additional processing when the Activities property changes.

(Inherited from CompositeActivity)

Event that occurs before a change being made to the underlying Activities.

(Inherited from CompositeActivity)

Called after changes have been made to the collection Activities of this instance.

(Inherited from CompositeActivity)
RaiseEvent(DependencyProperty, Object, EventArgs)

Raises an Event associated with the specified dependency property.

(Inherited from Activity)
RaiseGenericEvent<T>(DependencyProperty, Object, T)

Raises the event associated with the referenced DependencyProperty.

(Inherited from Activity)
RegisterForStatusChange(DependencyProperty, IActivityEventListener<ActivityExecutionStatusChangedEventArgs>)

Registers the specified DependencyProperty for the status change event.

(Inherited from Activity)
RemoveHandler(DependencyProperty, Object)

Removes an EventHandler from an associated DependencyProperty.

(Inherited from DependencyObject)

Removes a DependencyProperty from the DependencyObject.

(Inherited from DependencyObject)

Writes the Activity to a Stream for persistence.

(Inherited from Activity)
Save(Stream, IFormatter)

Writes the Activity to a Stream for persistence using the custom IFormatter provided for serialization.

(Inherited from Activity)
SetBinding(DependencyProperty, ActivityBind)

Sets the ActivityBind for the specified DependencyProperty.

(Inherited from DependencyObject)
SetBoundValue(ActivityBind, Object)

Sets the value of the target ActivityBind.

(Inherited from DependencyObject)
SetReadOnlyPropertyValue(DependencyProperty, Object)

Sets the value of a DependencyProperty, which is read-only.

(Inherited from DependencyObject)
SetValue(DependencyProperty, Object)

Sets the value of the DependencyProperty to the object.

(Inherited from DependencyObject)
SetValueBase(DependencyProperty, Object)

Sets the value of the DependencyProperty to the specified Object, bypassing the SetValue(DependencyProperty, Object).

(Inherited from DependencyObject)

Provides a string that represents this instance.

(Inherited from Activity)

Informs the run-time tracking infrastructure of pending tracking information.

(Inherited from Activity)
TrackData(String, Object)

Informs the run-time tracking infrastructure of pending tracking information.

(Inherited from Activity)

Called by the workflow runtime engine when an activity transitions into the Closed state from the Initialized state.

(Inherited from CompositeActivity)
UnregisterForStatusChange(DependencyProperty, IActivityEventListener<ActivityExecutionStatusChangedEventArgs>)

Un-registers the specified DependencyProperty for the status change event.

(Inherited from Activity)



Occurs when the activity execution is canceled.

(Inherited from Activity)

Occurs when an Activity has completed execution.

(Inherited from Activity)

Occurs when running a compensation method on the Activity.

(Inherited from Activity)

Occurs when the Activity is run.

(Inherited from Activity)

Occurs when an exception is raised during the running of the instance.

(Inherited from Activity)

Occurs when the ActivityExecutionStatus of a running Activity changes.

(Inherited from Activity)

Explicit Interface Implementations

IActivityEventListener<ActivityExecutionStatusChangedEventArgs>.OnEvent(Object, ActivityExecutionStatusChangedEventArgs)

Defines the processing procedure when the subscribed-to event occurs.


Represents the method that handles the Disposed event of a component.

(Inherited from DependencyObject)

Applies to

See also