为什么.net委托分配运算符未将引用分配给原始委托？ [英] Why .net delegate assignment operator is not assigning the reference to the original delegate?

问题描述

为什么copyOfDelegate是原始委托的副本，而不是原始委托的引用副本？

Why the copyOfDelegate is a copy of the original delegate, instead of the reference copy of the original one?

    public class DelegateTester
    {
        public delegate void PrintDelegate();

        public PrintDelegate PrintCallback;
    }

    public class Client
    {
        public void Print()
        {
            Console.WriteLine("in client");
        }
    }



   static void main()     
   {  
      DelegateTester tester = new DelegateTester();
      Client client = new Client();

      tester.PrintCallback += new DelegateTester.PrintDelegate(client.Print);
      tester.PrintCallback += new DelegateTester.PrintDelegate(client.Print);

      // copy the delegate
      DelegateTester.PrintDelegate copyOfDelegate = tester.PrintCallback;
      tester.PrintCallback -= new DelegateTester.PrintDelegate(client.Print);

      tester.PrintCallback();
      copyOfDelegate.Invoke();
    }

推荐答案

我相信代表是不可变的，因此，在您设置的位置：

I believe delegates are immutable, so where you have set:

copyOfDelegate = tester.PrintCallback;

然后：

PrintCallback -= new DelegateTester.PrintDelegate(client.Print);

您实际上已将原始委托实例分配给 copyOfDelegate ，然后由于不可变性而将其分配给 Printcallback 时，将创建一个新的委托。

You've actually assigned the original delegate instance to copyOfDelegate, and then a new delegate is created when you assign to Printcallback because of the immutability.

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