委托方法与通用方法 [英] Delegate Methods vs General Methods

问题描述

我想知道使用委托方法和使用通用方法[没有委托]的区别.

I want to know the difference between using Delegate Methods and using General Methods[without Delegates].

使用委托:

delegate void DelMethod(string str);

static void Method(string str)
{
    Debug.WriteLine(str);
}

用法:

DelMethod dm = new DelMethod(Method);
dm(string);

---

并且没有委托:

static void Method(string str)
{
    Debug.WriteLine(str);
}

用法:

Method(string)

---

这两者有什么区别??

---

What are the differences of these two??

没有委托的方法更小更容易.但我发现编码人员经常使用委托方法.

The method without delegate is smaller and easy. But I find coders using delegated Methods frequently.

这背后的原因是什么??

What is the reason behind this??

推荐答案

代表是针对另一种情况的.想象一下，你有一个班级应该回答另一个班级的问题，但你对第二个班级一无所知.在这种情况下，您可以先做一个委托.

Delegates are for another situation. Imagine, that you have a class which should answer for something from another class, but you know nothing about the second class. In such situation you can do a Delegate in the first.

// class where you know something
class A
{
   //delegate for answer
   public Func<bool> AskForSomething { get; set; }

   public void DoSomething()
   {
      //some code
      if(AskForSomething())
      {
          //do something
      }
      else
      {
          //do something else
      }
   }
}

class B
{
   public void Test()
   {
      A a = new A();
      a.AskForSomething = new Func<bool>(Answer);
      a.DoSomething();
   }

   private bool Answer()
   {
       return true;
   } 
}

Class A 对class B 一无所知，但它可以调用B 的方法并得到它的结果.class B中的Answer方法是private，class A不能直接调用.

Class A knows nothing about class B, but it can call B's methods and get it's results. The Answer method in class B is private and class A can't call it directly.

在 MSDN

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