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//定义部分
type
TForm1 = class(TForm)
btn1: TButton;
procedure btn1Click(Sender: TObject);
private
procedure UserMethod(msg: string); //委托指定的用户自定义方法
{ Private declarations }
public
{ Public declarations }
end;
type
TParent = class
private
a: Integer;
public
constructor Create();
procedure geta;
end;
TssnEditorEvent = class
private
// 回调函数指针
m_OnEditorChange: TNotifyEvent;
public
procedure OnEditorSelectionChange(Sender: TObject);
procedure SetOnEditorSelectionChange(Value: TNotifyEvent);
end;
//使用部分,
var
g_EditorEvent: TssnEditorEvent = nil;
procedure TForm1.btn1Click(Sender: TObject);
var
p: TParent;
e: TssnEditorEvent;
begin
//
p := TParent.Create;
e := TssnEditorEvent.Create;
e.SetOnEditorSelectionChange(UserMethod);
p.geta;
e.Free;
p.Free;
end;
procedure TForm1.UserMethod(msg: string);
begin
showmessage(msg);
end;
{ TParent }
constructor TParent.Create;
begin
a := 1;
end;
procedure TParent.geta;
begin
g_EditorEvent.OnEditorSelectionChange(nil);
ShowMessage('from a class named parent: ' + IntToStr(a));
end;
{ TssnEditorEvent }
procedure TssnEditorEvent.OnEditorSelectionChange(Sender: TObject);
begin
if Assigned(m_OnEditorChange) then
m_OnEditorChange(Sender); // 调用回调函数
end;
procedure TssnEditorEvent.SetOnEditorSelectionChange(Value: TNotifyEvent);
begin
m_OnEditorChange := Value;
end;