Prevent opening multiple instance of VB application

问题

I'm working on VB6 application, which is connected to MS Access database, so I don't want to allow user to open multiple instances of my application as this will create conflicts & alter connected database. Also, if user tries to open another instance, the currently running instance must be focused. How can I attain this? Thanks in advance.......... :-)

回答1:

Use App.PrevInstance:

'this code would be in a bas module for start up.'
Private Sub main()
    'Check for previous instance and exit if found.'

    Dim rc As Long

    If App.PrevInstance Then
        rc = MsgBox("Application is already running", vbCritical, App.Title)
        Exit Sub
    Else
        frmMain.Show
    End If

End Sub

来源：https://stackoverflow.com/questions/3468616/prevent-opening-multiple-instance-of-vb-application