防止程序重复执行的单元
//工程引用此单元就能防止同时出现多个实例 unit MultInst; interface uses Windows ,Messages, SysUtils, Classes, Forms; implementation const STR_UNIQUE = '{2BE6D96E-827F-4BF9-B33E-8740412CDE96}'; MI_ACTIVEAPP = 1; {激活应用程序} MI_GETHANDLE = 2; {取得句柄} var iMessageID : Integer; OldWProc : TFNWndProc; MutHandle : THandle; BSMRecipients : DWORD; function NewWndProc(Handle: HWND; Msg: Integer; wParam, lParam: Longint): Longint; stdcall; begin Result := 0; if Msg = iMessageID then begin case wParam of MI_ACTIVEAPP: {激活应用程序} if lParam<>0 then begin {收到消息的激活前一个实例} {为什么要在另一个程序中激活?} {因为在同一个进程中SetForegroundWindow并不能把窗体提到最前} if IsIconic(lParam) then OpenIcon(lParam) else SetForegroundWindow(lParam); Application.Terminate; {终止本实例} end; MI_GETHANDLE: {取得程序句柄} begin PostMessage(HWND(lParam), iMessageID, MI_ACTIVEAPP, Application.Handle); end; end; end else Result := CallWindowProc(OldWProc, Handle, Msg, wParam, lParam); end; procedure InitInstance; begin {取代应用程序的消息处理} OldWProc := TFNWndProc(SetWindowLong(Application.Handle, GWL_WNDPROC, Longint(@NewWndProc))); {打开互斥对象} MutHandle := OpenMutex(MUTEX_ALL_ACCESS, False, STR_UNIQUE); if MutHandle = 0 then begin {建立互斥对象} MutHandle := CreateMutex(nil, False, STR_UNIQUE); end else begin Application.ShowMainForm := False; {已经有程序实例,广播消息取得实例句柄} BSMRecipients := BSM_APPLICATIONS; BroadCastSystemMessage(BSF_IGNORECURRENTTASK or BSF_POSTMESSAGE, @BSMRecipients, iMessageID, MI_GETHANDLE,Application.Handle); end; end; initialization {注册消息} iMessageID := RegisterWindowMessage(STR_UNIQUE); InitInstance; finalization {还原消息处理过程} if OldWProc <> Nil then SetWindowLong(Application.Handle, GWL_WNDPROC, LongInt(OldWProc)); {关闭互斥对象} if MutHandle <> 0 then CloseHandle(MutHandle); end.
本文来自博客园,作者:{咏南中间件},转载请注明原文链接:https://www.cnblogs.com/hnxxcxg/archive/2008/08/25/2940829.html