构造自己的消息循环.docVIP

构造自己的消息循环 构造自己的消息循环 2005-09-06 13:51:47 只是个技巧,像TCustomForm.ShowModal方法就是构造了一个消息循环. 由于TApplication的几个消息处理函数是保护的,这里使用了一个技巧来访问它们. 下面的基类可以实现用rundll32.exe调用DLL中的窗体(是用SHOW方法显示窗体,如果不构建 消息循环,SHOW方法只是将窗体一闪而过,虽然直接用窗体的ShowModal方法也可以实现相似 的功能,但多窗体就会有些小问题,另外,下面的代码可以调用DLL中的MDI主窗体,但引出函 数要用Application.CreateForm方法建立MDI主窗体,还有些细节没有解决. {----------------------------------------------------------------------------- Unit Name: BaseDllFrm Author: ysai Purpose: DLL中的窗体,可以用rundll32.exe调用 History: -----------------------------------------------------------------------------} unit BaseDllFrm; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls; type TfrmBaseDll = class(TForm) private FEnterMsgLoop : Boolean; procedure EnterMsgLoop; protected procedure DoShow; override; procedure DoClose(var Action: TCloseAction); override; procedure SetZOrder(TopMost: Boolean); override; public CanExit : Boolean; function ShowModal: Integer; override; constructor Create(AOwner: TComponent); override; destructor Destroy; override; end; implementation {$R *.dfm} type //调用TApplication未公布的方法 TApplicationEx = class(TApplication) public function IsDlgMsg(var Msg: TMsg): Boolean; function IsHintMsg(var Msg: TMsg): Boolean; function IsKeyMsg(var Msg: TMsg): Boolean; function IsMDIMsg(var Msg: TMsg): Boolean; end; { TApplicationEx } function TApplicationEx.IsDlgMsg(var Msg: TMsg): Boolean; begin Result := inherited IsDlgMsg(Msg); end; function TApplicationEx.IsHintMsg(var Msg: TMsg): Boolean; begin Result := inherited IsHintMsg(Msg); end; function TApplicationEx.IsKeyMsg(var Msg: TMsg): Boolean; begin Result := inherited IsKeyMsg(Msg); end; function TApplicationEx.IsMDIMsg(var Msg: TMsg): Boolean; begin Result := inherited IsMDIMsg(Msg); end; { TfrmSetup } procedure TfrmBaseDll.EnterMsgLoop; //构建消息循环 var Handled : Boolean; Msg : TMsg; begin if FEnterMsgLoop then Exit; FEnterMsgLoop := True; CanExit:=False; while