匿名方法作为函数结果

本文介绍了匿名方法作为函数结果的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我想要做的是将一个匿名方法（作为函数结果我将它分配给相同类型的变量）。 Delphi抱怨无法完成分配任务。显然，Delphi的东西我想分配 GetListener函数而不是该函数的结果。非常感谢对此的任何帮助。

What I want to do is to assign an anonymous method which I get as a function result to a variable of the same type. Delphi complains about not beeing able to do the assignement. Obviously Delphi things I want to assign the "GetListener" function instead of the result of that same function. Any help with this is very much appreciated.

type TPropertyChangedListener = reference to procedure (Sender: TStimulus); TMyClass = class function GetListener:TPropertyChangedListener end; .... var MyClass: TMyClass; Listener: TPropertyChangedListener; begin MyClass:= TMyClass.create; Listener:= MyClass.GetListener; // Delphi compile error: E2010 Incompatible types: TPropertyChangedListener' and 'Procedure of object' end;

推荐答案

使用以下语法：

Listener:= MyClass.GetListener();

我已经写了以下示例来说明MyClass.GetListener（）和MyClass.GetListener分配之间的区别：

I have written the following example to make clear the difference between the MyClass.GetListener() and MyClass.GetListener assignments:

type TProcRef = reference to procedure(Sender: TObject); TFunc = function: TProcRef of object; TMyClass = class function GetListener: TProcRef; end; function TMyClass.GetListener: TProcRef; begin Result:= procedure(Sender: TObject) begin Sender.Free; end; end; procedure TForm1.Button1Click(Sender: TObject); var MyClass: TMyClass; ProcRef: TProcRef; Func: TFunc; begin MyClass:= TMyClass.Create; // standard syntax ProcRef:= MyClass.GetListener(); // also possible syntax // Func:= MyClass.GetListener; // ProcRef:= Func(); ProcRef(MyClass); end;