C＃如何实现“单一”方法

Question

We all know about the singleton pattern.

How do you implement a singleton "method"? - a method that is called only once and any other call will do nothing.

I can think a few ways (including Lazy - if (!.IsValueCreated) {... value.method();}) but how would you implement it?

Answer 1

I don't think so there is something like a singleton method.

If you want your method to do execute the block of code only once then you can do that. This can be done in several ways, one of them could be as follows-

   public class Foo
    {
      private static bool _isInitialied;


      public void Initialize()
      {
        if(_isInitialied) 
            return;
        //TODO: Initialization stups.
        _isInitialied = true;
      }
    }

Answer 2

You could achieve this using actions:

public class Test
{
    private Action _action;

    private void DoSomething()
    { 
        // Do something interesting
        _action = DoNothing;
    }

    private void DoNothing()
    {
    }

    public Test()
    {
        _action = DoSomething;
    }

    public void Call()
    {
        _action();
    }
} // eo class Test