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NativeActivity Class

Abstract base class for custom activities that implement execution logic using the Execute(ActivityExecutionContext) method, which has full access to the runtime’s features.


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

public abstract class NativeActivity : Activity

The NativeActivity type exposes the following members.

Protected methodNativeActivityWhen implemented in a derived class, creates a new instance of the derived class.

Protected propertyCacheIdGets the identifier of the cache that is unique within the scope of the workflow definition. (Inherited from Activity.)
Protected propertyCanInduceIdleGets or sets a value that indicates whether the activity can cause the workflow to become idle.
Protected propertyConstraintsGets a collection of Constraint activities that can be configured to provide validation for the Activity. (Inherited from Activity.)
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 propertyImplementationThe execution logic of the activity. (Overrides Activity.Implementation.)

Protected methodAbortWhen implemented in a derived class, takes actions in response to the activity being aborted.
Protected methodCacheMetadata(ActivityMetadata)Not implemented. Use the CacheMetadata(NativeActivityMetadata) method instead. (Overrides Activity.CacheMetadata(ActivityMetadata).)
Protected methodCacheMetadata(NativeActivityMetadata)Creates and validates a description of the activity’s arguments, variables, child activities, and activity delegates.
Protected methodCancelWhen implemented in a derived class, runs logic to cause graceful early completion of the activity.
Public methodEquals(Object)Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Protected methodExecuteWhen implemented in a derived class, runs the activity’s execution logic.
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodGetHashCodeServes as a hash function for a particular type. (Inherited from Object.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (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.)

The following code sample demonstrates creating a class that inherits from NativeActivity<TResult>. This example is from the Custom Composite using Native Activity sample.

public sealed class MySequence : NativeActivity
    Collection<Activity> children;
    Collection<Variable> variables;
    Variable<int> currentIndex;
    CompletionCallback onChildComplete;

    public MySequence()
        : base()
        this.children = new Collection<Activity>();
        this.variables = new Collection<Variable>();
        this.currentIndex = new Variable<int>();

    public Collection<Activity> Activities
            return this.children;
    public Collection<Variable> Variables
            return this.variables;
    protected override void CacheMetadata(NativeActivityMetadata metadata)
        //call base.CacheMetadata to add the Activities and Variables to this activity's metadata
        //add the private implementation variable: currentIndex 

    protected override void Execute(NativeActivityContext context)
        InternalExecute(context, null);
    void InternalExecute(NativeActivityContext context, ActivityInstance instance)
        //grab the index of the current Activity
        int currentActivityIndex = this.currentIndex.Get(context);
        if (currentActivityIndex == Activities.Count)
            //if the currentActivityIndex is equal to the count of MySequence's Activities
            //MySequence is complete

        if (this.onChildComplete == null)
            //on completion of the current child, have the runtime call back on this method
            this.onChildComplete = new CompletionCallback(InternalExecute);
        //grab the next Activity in MySequence.Activities and schedule it
        Activity nextChild = Activities[currentActivityIndex];
        context.ScheduleActivity(nextChild, this.onChildComplete);

        //increment the currentIndex
        this.currentIndex.Set(context, ++currentActivityIndex);

.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.

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

      System.Activities.Statements.InvokeAction<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10>
      System.Activities.Statements.InvokeAction<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11>
      System.Activities.Statements.InvokeAction<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12>
      System.Activities.Statements.InvokeAction<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13>
      System.Activities.Statements.InvokeAction<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14>
      System.Activities.Statements.InvokeAction<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15>
      System.Activities.Statements.InvokeAction<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16>
      System.Activities.Statements.InvokeAction<T1, T2>
      System.Activities.Statements.InvokeAction<T1, T2, T3>
      System.Activities.Statements.InvokeAction<T1, T2, T3, T4>
      System.Activities.Statements.InvokeAction<T1, T2, T3, T4, T5>
      System.Activities.Statements.InvokeAction<T1, T2, T3, T4, T5, T6>
      System.Activities.Statements.InvokeAction<T1, T2, T3, T4, T5, T6, T7>
      System.Activities.Statements.InvokeAction<T1, T2, T3, T4, T5, T6, T7, T8>
      System.Activities.Statements.InvokeAction<T1, T2, T3, T4, T5, T6, T7, T8, T9>