C＃+替代委托

Question

I have some code that is using a third-party library that I can't bypass. This library provides some auxiliary features that I need. At this time, my code is setup like this:

static Engine engine = new Engine();

static void Main(string[] args)
{
   engine.Execute(MyCode); 
}

private static void MyCode()
{
  // my code goes here
}

Here's my challenge: I have to instantiate some code before MyCode can use it because that instantiation must hit a database and takes longer than the threshold allowed by Engine . I can't use a static variable because multiple instances will be necessary. Which basically means, I want something like this:

static Engine engine = new Engine();

static void Main(string[] args)
{
   MyClass c = new MyClass();
   c.Initialize();  // This is the db call

   engine.Execute(MyCode); // This line is the problem
}

private static void MyCode(MyClass c)
{
  // my code goes here
  c.DoStuff();
}

My problem is, I basically need to create an overloaded method that takes a parameter. However, the Execute method in the third-party library doesn't let me do that. Is there some C# syntactial way I can do this that I'm missing?

Answer 1

您正在寻找lambda表达式：

engine.Execute(() => MyCode(c));

Answer 2

I'm assuming that Engine.Execute takes an instance of Action .

You could make the MyCode function an instance member function on MyClass , then pass MyClass.MyCode to Engine.Execute as an Action .

public class Engine
{
    public void Execute(Action action)
    {
        action.Invoke();
    }
}

public class MyClass
{
    public void Initialize()
    {
        System.Threading.Thread.Sleep(500); //Simulate some work.
    }

    public void Run()
    {
        // I've renamed it from MyCode to Run, but this method is essentially your
        // my code method.
        Console.WriteLine($"I'm being run from the engine! My Id is {_id}.");
    }

    private readonly Guid _id = Guid.NewGuid();
}

public static class Program
{
   static void Main(string[] args)
   {
      var engine = new Engine();
      var c = new MyClass();
      c.Initialize();
      engine.Execute(c.Run);
   }
}