Delphi拾遗（8） 类事件

类的事件
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;
type
TMyEvent = procedure of object; //不带参数的过程
TMyEventExt = procedure(AName: string) of object; //带参数的过程

TForm1 = class(TForm)
Button1: TButton;
Button2: TButton;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
TMyBase = class
private
FName : string;
FAge : Integer;
FOnEvent: TMyEvent; //定义 TMyEvent 类型事件
FOnEventExt: TMyEventExt;
procedure SetAge(const AValue: Integer);
public
//创建类时进行相应的一些初始化工作
constructor Create;
procedure SetEvent1;
procedure SetEvent2;
procedure SetEventExt1(ATmp: string);
//Name属性 不可更改
property Name: string read FName write FName;
//Age属性 可以更改
property Age: Integer read FAge write SetAge;
//关联事件 发布 TMyEvent 类型事件
property OnEvent: TMyEvent read FOnEvent write FOnEvent;
property OnEventExt: TMyEventExt read FOnEventExt write FOnEventExt;
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
{ TMyBase }
constructor TMyBase.Create;
begin
FName := 'hehf';
FAge := 99; //不赋值时默认为0
FOnEvent := SetEvent1;
FOnEventExt := SetEventExt1; //这时不能带参数
end;
procedure TMyBase.SetAge(const AValue: Integer);
begin
if (AValue > 0) and (AValue < 130) then
FAge := AValue
else
FAge := -1;
end;
procedure TForm1.Button1Click(Sender: TObject);
var
TmpMy: TMyBase;
begin
TmpMy := TMyBase.Create;
ShowMessage(IntToStr(TmpMy.Age)); // 99
TmpMy.Age := 100;
ShowMessage(IntToStr(TmpMy.Age)); // 100
TmpMy.OnEvent; //触发关联事件
TmpMy.Free;
end;
procedure TMyBase.SetEvent1;
begin
ShowMessage('Event 1'