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;更多推荐
匿名方法作为函数结果
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