NativeActivity Classe

Definizione

public ref class NativeActivity abstract : System::Activities::Activity

public abstract class NativeActivity : System.Activities.Activity

type NativeActivity = class
    inherit Activity

Public MustInherit Class NativeActivity
Inherits Activity

Ereditarietà

Object

Activity

NativeActivity

Derivato

System.Activities.Statements.CancellationScope

System.Activities.Statements.Compensate

System.Activities.Statements.Confirm

System.Activities.Statements.Delay

System.Activities.Statements.DeleteBookmarkScope

Altro…

Esempio

Nell'esempio di codice seguente viene illustrata la creazione di una classe che eredita da NativeActivity<TResult>. Questo esempio proviene dall'esempio personalizzato composito usando l'attività nativa .

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

        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);
    }
}