如何传递一个对象方法作为参数在Delphi，然后调用它？ [英] How to Pass an Object Method as a Parameter in Delphi, and then Call It?

问题描述

我恐怕这可能是一个虚假的问题，但它有我很累的。

I fear this is probably a bit of a dummy question, but it has me pretty stumped.

我正在寻找最简单的方法可能传递一个方法的对象到过程中，以便过程可以调用对象的方法（例如在超时后，或者可能在不同的线程中）。所以基本上我想：

I'm looking for the simplest way possible to pass a method of an object into a procedure, so that the procedure can call the object's method (e.g. after a timeout, or maybe in a different thread). So basically I want to:

• 捕获对象方法的引用。

我想我可以使用接口实现相同的效果，但我认为有另一种方式，因为这个对象的过程类型声明存在。

I figure I could achieve the same effect using interfaces, but I thought there was another way, since this "procedure of object" type declaration exists.

以下不会工作，但可能有助于解释我感到困惑...？

The following doesn't work, but might it help explain where I'm confused...?

interface 
  TCallbackMethod = procedure of object;

  TCallbackObject = class
    procedure CallbackMethodImpl;
    procedure SetupCallback;
  end;

implementation

procedure CallbackTheCallback(const callbackMethod: TCallbackMethod);
begin
  callbackMethod();
end;

procedure TCallbackObject.CallbackMethodImpl;
begin
  // Do whatever.
end;

procedure TCallbackObject.SetupCallback;
begin
  // following line doesn't compile - it fails with "E2036 Variable required"
  CallbackTheCallback(@self.CallbackMethodImpl);
end;

（一旦问题得到解答，我将删除上述代码，除非它有助于解释。

(Once the question is answered I'll remove the above code unless it aids the explanation somehow.)

推荐答案

只需删除指针内容即可。 Delphi会为你做：

Just remove the Pointer stuff. Delphi will do it for you:

procedure TCallbackObject.SetupCallback;
begin
  CallbackTheCallback(CallbackMethodImpl);
end;

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