捕获/创建TCustomControl Delphi的OnGetFocus / OnLostFocus事件
发布时间:2020-12-15 09:51:22 所属栏目:大数据 来源:网络整理
导读:我创建了一个继承自TCustomControl的Delphi组件.该组件可以从TWinControl继承而成为焦点,但是当它聚焦时我需要“突出显示”并在失去焦点时更改某些属性. 正如Delphi文档所说,TCustomControl没有继承的OnFocus事件,所以我需要捕获事件(?)并实现我自己的OnGet
我创建了一个继承自TCustomControl的Delphi组件.该组件可以从TWinControl继承而成为焦点,但是当它聚焦时我需要“突出显示”并在失去焦点时更改某些属性.
正如Delphi文档所说,TCustomControl没有继承的OnFocus事件,所以我需要捕获事件(?)并实现我自己的OnGetFocus / OnLostFocus事件处理程序(?). 当组件获得/失去焦点时,如何捕获事件? 解决方法
控件接收或丢失输入焦点时触发的事件是
OnEnter 和
OnExit ,并从作为组件开发人员应覆盖的
DoEnter 和
DoExit 方法触发:
type TMyControl = class(TCustomControl) protected procedure DoEnter; override; procedure DoExit; override; end; implementation { TMyControl } procedure TMyControl.DoEnter; begin inherited; // the control received the input focus,so do what you need here; note // that it's recommended to call inherited inside this method (which as // described in the reference should only fire the OnEnter event now) end; procedure TMyControl.DoExit; begin inherited; // the control has lost the input focus,so do what you need here; note // that it's recommended to call inherited inside this method (which as // described in the reference should only fire the OnExit event now) end; (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |