首先代碼創建Activity:

 public sealed class WaitForResponse<TResult>:NativeActivity<TResult>
    {
        public WaitForResponse()
            :base()
        {}

        public string ResponseName { get; set; }

        protected override bool CanInduceIdle => true;

        protected
 
 override void Execute(NativeActivityContext context)
        {
            context.CreateBookmark(this.ResponseName, new BookmarkCallback(this.ReceivedResponse)); //這裏加入BookmarkCallback, 用來設置返回值
        }

        void ReceivedResponse(NativeActivityContext context,Bookmark bookmark,object obj)
        {
            
 
this.Result.Set(context, (TResult)obj);
        }
    }

創建Workflow:

在Branch1中創建一個變量myVar, 然後在創建的Activity中設置Result為myVar, 這個myVar會接收這個Activity創建Bookmark時返回的值.

測試:

public partial class Form1 : Form
    {
        static WorkflowApplication wfapp;
        public Form1()
        {
            InitializeComponent();
        }

        
 
private void button1_Click(object sender, EventArgs e)
        {
            wfapp = new WorkflowApplication(new ActivityLibrary1.Activity1());
            wfapp.Idle = MyIdle;
            wfapp.Run();

            ThreadPool.QueueUserWorkItem(ReadName); //傳入的關鍵, 不然workflow不會resume, Pick會運行到Branch2中去
        }

        void MyIdle(WorkflowApplicationIdleEventArgs e)
        {
            Console.WriteLine("Idle:" + e.InstanceId);
        }

        static void ReadName(object state)
        {
            string text = "abc";

            // Resume the Activity that set this bookmark (ReadString).
           Form1.wfapp.ResumeBookmark("P1", text);         
           
        }
    }

有返回值的Bookmark