我想创建一个自定义的活动WF4该主机的子活动，并传递一些参数到它的子活动。我在下面附上我的活动的简化版本（亲子）

I am trying to create a custom activity for WF4 that host a child activity and pass some arguments to its child activity. I attach below a simplified version of my activities (Parent and Child)

public class Child : CodeActivity
{
    public InArgument<Dictionary<string, object>> Data;

    protected override void Execute(CodeActivityContext context)
    {
        Dictionary<string, object> data = Data.Get(context);

        //Some operations on the input data
    }
}


 public class Parent : NativeActivity
{
    public InArgument<int> Value1 { get; set; }

    public InArgument<string> Value2 { get; set; }

    public Child Body { get; set; }


    protected override void Execute(NativeActivityContext context)
    {
        int value1 = Value1.Get(context);
        string value2 = Value2.Get(context);

        Dictionary<string, object> data = new Dictionary<string, object>();
        data.Add("value1", value1);
        data.Add("value2", value2);

        context.SetValue(Body.Data, data);

        context.ScheduleActivity(this.Body);
    }


    protected override void CacheMetadata(NativeActivityMetadata metadata)
    {
        Body = new Child();

        base.CacheMetadata(metadata);
    }
}

从子活动的数据参数为空时，工作流执行到该活动的执行方式。

The Data argument from the Child activity is null when the workflow execution reaches the Execute method for the activity.

有人可以请给我一些指导如何参数在此两项活动之间传递？

Can someone please, give me some direction how could the arguments be passed between this two activities?

推荐答案

虽然有额外的变量的方法适用安排一个孩子与一些投入的官方的方法是使用ActivityAcytion或者如果你也希望有一个结果，与ActivityFunc。

While the approach with the extra variable works the "official" way of scheduling a child with some inputs is using in ActivityAcytion or if you also want a result with an ActivityFunc.

恐怕code并没有真正得到任何简单或更容易理解，但为了完整起见我决定添加此。

I am afraid the code doesn't really get to be any simpler or easier to understand but for completeness sake I just decided to add this.

public class Child : CodeActivity<object>
{
    public InArgument<Dictionary<string, object>> Data { get; set; }

    protected override object Execute(CodeActivityContext context)
    {
        Dictionary<string, object> data = Data.Get(context);

        foreach (var item in data)
        {
            Console.WriteLine(item);
        }

        return "Some result";
    }
}



public class Parent : NativeActivity<object>
{
    public InArgument<int> Value1 { get; set; }
    public InArgument<string> Value2 { get; set; }

    public ActivityFunc<Dictionary<string, object>, object> Body { get; set; }

    protected override void Execute(NativeActivityContext context)
    {
        int value1 = Value1.Get(context);
        string value2 = Value2.Get(context);

        Dictionary<string, object> data = new Dictionary<string, object>();
        data.Add("value1", value1);
        data.Add("value2", value2);

        context.ScheduleFunc<Dictionary<string, object>, object>(Body, data, ChildCompletionCallback);
    }


    protected override void CacheMetadata(NativeActivityMetadata metadata)
    {
        var arg = new DelegateInArgument<Dictionary<string, object>>();

        Body = new ActivityFunc<Dictionary<string, object>, object>
        {
            Argument = arg,
            Handler = new Child() { Data = arg }
        };

        base.CacheMetadata(metadata);
    }

    private void ChildCompletionCallback(NativeActivityContext context, ActivityInstance completedInstance, object result)
    {
        //Set the output for the parent activity at the completion of the child activity
        this.Result.Set(context, result);
    }
}