本文介绍了调用具有多个具有返回值的函数的委托的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!

问题描述

我正在尝试理解代表的概念并提出了疑问。假设我们有一个委托,其返回类型定义为int并接受2个类型为int的参数。

I am trying to understand concept of delegates and have got a query. Suppose that we have a delegate defined with return type as int and accepting in 2 parameters of type int.

委托声明:

 public delegate int BinaryOp(int x, int y);

现在,假设我们有2个方法(加法和乘法)都接受2个int参数并返回结果。

Now, lets say we have 2 methods (add and multiply) both accepting 2 int parameters and returning an int result.

代码:

    static int Add(int x, int y)
   {
        return x + y;
    }

    static int Multiply(int x, int y)
   {
        return x * y;
    }

现在,将添加和乘法方法添加到此委托中,然后委托的调用方式如下:

Now, when add and multiply methods are added into this delegate, and then when the delegate is called like:

BinaryOp b = new BinaryOp(Add);
b+=new BinaryOp(Multiply);

int value=delegate_name(2,3);

然后,根据我的理解,两种方法都被调用了。现在,这两种方法的结果存储在value变量中?还是在这种情况下返回数组?

Then, as per my understanding, both the methods are called. Now, result from which of the 2 methods is stored in the value variable? Or does it return an array in such case?

推荐答案

实际上,通过一些技巧和转换,您可以得到所有结果如下:

Actually, with a little bit of trickery and casting, you can get all of the results like this:

var b = new BinaryOp(Add);
b += new BinaryOp(Multiply);

var results = b.GetInvocationList().Select(x => (int)x.DynamicInvoke(2, 3));
foreach (var result in results)
    Console.WriteLine(result);

输出:

5
6

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08-04 13:31
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