How to prevent a second instance of an application.

  • Thread starter Thread starter Totto
  • Start date Start date
T

Totto

Hi
How do I prevent a program from beeing started more than one time.
IE. If a dot net app is already started how do I prevent a second instance
to be started ?

Tnx
Totto
 
Option Strict On
Imports System.Threading

Module Main
Private Sub SubMain()

SingletonApp.Run(New MyForm)

End Sub
Enc Module


Public Class SingletonApp

Shared m_Mutex As Mutex
Public Shared Sub Run(ByVal mainForm As Form)
If (IsFirstInstance()) Then
AddHandler Application.ApplicationExit, AddressOf OnExit
Application.Run(mainForm)
End If
End Sub
Public Shared Function IsFirstInstance() As Boolean

' use this to create a unique guid for your app...
'Dim g As New Guid
'g = Guid.NewGuid
'Debug.WriteLine(g.ToString)

m_Mutex = New Mutex(False, "8ca35a66-6e9a-41d4-a87d-d9755b1f88c4") '
arbitrary GUID
Dim owned As Boolean = False
owned = m_Mutex.WaitOne(TimeSpan.Zero, False)
Return owned
End Function

Public Shared Sub OnExit(ByVal sender As Object, ByVal args As
EventArgs)
m_Mutex.ReleaseMutex()
m_Mutex.Close()
End Sub
End Class

HTH,
Greg
 
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