Rx.Net:在SelectMany中调用多个IObservable [英] Rx.Net : Calling multiple IObservable in SelectMany

问题描述

请注意:这是问题较早发布，但感兴趣的解决方案却有不同的情况.

Please Note: This is continuation of the question posted earlier but the solution of interest is of a different situation.

我试图多次调用各自返回IObservable的方法，但在SelectMany语句中返回的值是一个Task，因此下面的Subscribe语句无法编译.

I am trying to make multiple calls to the methods that each return IObservable but the values being returned back in the SelectMany statement is a Task and hence the following Subscribe statement does not compile.

这是代码段

 var myWorkList = new List<MyWork>
                {
                    new MyWork(),// MyWork.Execute(data) returns IObservable
                    new MyWork()
                }.ToObservable();

 var results =
   myService
    .GetData(accountId)
    .SelectMany(data => myWorkList.ForEachAsync(r => r.Execute(data))
    .Subscribe(result =>
    {
        Console.WriteLine($"Result Id: {result.Id}");
        Console.WriteLine($"Result Status: {result.Pass}");
    });

推荐答案

您只想使用.SelectMany.试试这个:

You just want to use .SelectMany. Try this:

var myWorkList = new List<MyWork>()
{
    new MyWork(),
    new MyWork()
}.ToObservable();

var query =
    from data in myService.GetData(accountId)
    from myWork in myWorkList
    from result in myWork.Execute(data)
    select result;

var results =
    query
        .Subscribe(result =>
        {
            Console.WriteLine($"Result Id: {result.Id}");
            Console.WriteLine($"Result Status: {result.Pass}");
        });

这是我的测试代码:

public static class myService
{
    public static IObservable<MyData> GetData(int x)
        => Observable.Return(new MyData());
}

public class MyWork
{
    public virtual IObservable<MyResult> Execute(MyData data)
    {
        return
            from isMatch in IsMatch(data)
            where isMatch
            select new MyResult() { Id = 1, Pass = true };
    }

    public IObservable<bool> IsMatch(MyData data)
    {
        return Observable.Return(true);
    }
}

public class MyResult
{
    public int Id;
    public bool Pass;
}

public class MyData { }

当我执行我得到这个:

Result Id: 1
Result Status: True
Result Id: 1
Result Status: True

---

在对上一个问题的评论中，我建议将此作为代表列表进行.方法如下:

---

In the comments on your previous question I suggested doing this as a list of delegates. Here's how:

var myWorkList = new Func<MyData, IObservable<MyResult>>[]
{
    md => new MyWork().Execute(md),
    md => new MyWork().Execute(md),
}.ToObservable();

var query =
    from data in myService.GetData(accountId)
    from myWork in myWorkList
    from result in myWork(data)
    select result;

您得到相同的结果.

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