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reactive-programming system.reactive .net c#

Cheng Chen · 技术社区 · 15 年前

这是 an easy program to introduce the Reactive Framework . 但我想尝试错误处理程序,将程序修改为:

var cookiePieces = Observable.Range(1, 10);
cookiePieces.Subscribe(x =>
   {
      Console.WriteLine("{0}! {0} pieces of cookie!", x);
      throw new Exception();  // newly added by myself
   },
      ex => Console.WriteLine("the exception message..."),
      () => Console.WriteLine("Ah! Ah! Ah! Ah!"));
Console.ReadLine();

public static IDisposable Subscribe<TSource>(
     this IObservable<TSource> source, 
     Action<TSource> onNext, 
     Action<Exception> onError, 
     Action onCompleted);

我希望看到打印的异常消息,但是控制台应用程序崩溃了。原因是什么?

3 回复 | 直到 13 年前

Jon Skeet 15 年前

异常处理程序用于在可观察对象本身而不是由观察者创建的异常。

引发异常处理程序的简单方法如下:

using System;
using System.Linq;

class Test
{
    static void Main(string[] args)
    {
        var xs = Observable.Range(1, 10)
                           .Select(x => 10 / (5 - x));

        xs.Subscribe(x => Console.WriteLine("Received {0}", x),
                     ex => Console.WriteLine("Bang! {0}", ex),
                     () => Console.WriteLine("Done"));

        Console.WriteLine("App ending normally");
    }
}

输出:

Received 2
Received 3
Received 5
Received 10
Bang! System.DivideByZeroException: Attempted to divide by zero.
   at Test.<Main>b__0(Int32 x)
   at System.Linq.Observable.<>c__DisplayClass35a`2.<>c__DisplayClass35c.<Select
>b__359(TSource x)
App ending normally