从网上转过来的,没有试过,你可以参考一下:
unitMultInst;
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;
functionNewWndProc(Handle:HWND;Msg:Integer;wParam,lParam:Longint):
Longint;stdcall;
begin
Result:=0;
ifMsg=iMessageIDthen
begin
casewParamof
MI_ACTIVEAPP://激活应用程序
iflParam0then
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
ifIsIconic(lParam)then
OpenIcon(lParam)
else
SetForegroundWindow(lParam);
//终止本实例
Application.Terminate;
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;
procedureInitInstance;
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);
ifMutHandle=0then
begin
//建立互斥对象
MutHandle:=CreateMutex(nil,False,STR_UNIQUE);
end
elsebegin
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_IGNORECURRENTTASKorBSF_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
ifOldWProcNilthen
SetWindowLong(Application.Handle,GWL_WNDPROC,LongInt(OldWProc));
//关闭互斥对象
ifMutHandle0thenCloseHandle(MutHandle);
end.
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