Delphi中简单的回调函数

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回调函数的说明：回调函数（callback）是什么？ - 知乎  https://www.zhihu.com/question/19801131

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了解一下这个：Delphi 中三种回调函数形式解析 - 码农的笔记 - 博客园  https://www.cnblogs.com/dmqhjp/p/14776209.html

有必要

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----------------------------------------------开发环境-D7

------Unit开始

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls ;

type
TFCall=function(i:integer):string; //回调函数类型声明
TForm1 = class(TForm)
Button2: TButton;
procedure Button2Click(Sender: TObject);
private
{ Private declarations }
public
function GetStr(F:TFCall; i:integer):string;
{ Public declarations }
end;
var
Form1: TForm1;

implementation

{$R *.dfm}
function FCallBack01(i:integer):string; //回调函数定义
begin
Result:=IntToStr(i)+'100';
end;
procedure TForm1.Button2Click(Sender: TObject);
begin
ShowMessage(GetStr(FCallBack01,22));
end;

function TForm1.GetStr(F: TFCall; i:integer): string;
begin
Result:=F(i);
end;

end.

---------------unit结束

-----------Form开始

object Form1: TForm1
Left = 756
Top = 527
Width = 263
Height = 146
Caption = 'Form1'
Color = clBtnFace
Font.Charset = DEFAULT_CHARSET
Font.Color = clWindowText
Font.Height = -11
Font.Name = 'MS Sans Serif'
Font.Style = []
OldCreateOrder = False
PixelsPerInch = 96
TextHeight = 13
object Button2: TButton
Left = 64
Top = 40
Width = 75
Height = 25
Caption = 'Button2'
TabOrder = 0
OnClick = Button2Click
end
end

---------------Form结束

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另一个：Delphi中回调函数的简单例子 - 码农的笔记 - 博客园  https://www.cnblogs.com/dmqhjp/p/14772029.html