有时候,我们只能允许程序单实例运行,以免程序运行出错。可以通过使用App.PrevInstance和系统级的Mutex等多种办法来实现。
代码如下:
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'电子邮箱:31319180@qq.comOption ExplicitPrivate Declare Function CreateMutex Lib "kernel32.dll" Alias "CreateMutexA" (ByRef lpMutexAttributes As SECURITY_ATTRIBUTES, ByVal bInitialOwner As Long, ByVal lpName As String) As Long
Private Declare Function CloseHandle Lib "kernel32.dll" (ByVal hObject As Long) As LongPrivate Const ERROR_ALREADY_EXISTS As Long = 183&Private Type SECURITY_ATTRIBUTESnLength As LonglpSecurityDescriptor As LongbInheritHandle As Long
End TypeDim hAppMutex As LongPrivate Sub Form_Initialize()'方法1: 使用 App.PrevInstance 这种办法,只要EXE文件改个名字就可以运行多个实例。If App.PrevInstance ThenMsgBox "方法1: 使用 App.PrevInstance 这种办法,只要EXE文件改个名字就可以运行多个实例。"EndEnd If'方法2: 使用系统级的Mutex,改名字也没有用。If IsRunning ThenMsgBox "方法2: 使用系统级的Mutex,改名字也没有用。"EndEnd IfEnd SubPrivate Function IsRunning() As BooleanDim sa As SECURITY_ATTRIBUTESsa.bInheritHandle = 1sa.lpSecurityDescriptor = 0sa.nLength = Len(sa)hAppMutex = CreateMutex(sa, 1, "31319180@qq.com") ' 这里请使用自己的标志字符串或者 GUID 字符串If (Err.LastDllError = ERROR_ALREADY_EXISTS) ThenCloseHandle hAppMutexIsRunning = TrueEnd IfEnd FunctionPrivate Sub Form_Terminate()CloseHandle hAppMutex
End Sub