I'm trying to check in my application if another instance of it is
already running. I found many code snippets on the net that make use of
a named mutex to do this check, but I can't make it work on visual
basic. Actually, it works sometimes and sometimes not. The code I'm
trying is:
Namespace WindowsApplicat ion2
Public Class Form1
Inherits Form
Public Sub New()
End Sub
Private Shared appGuid As String = "uniquekeyonmym achine"
Public Shared Sub Main()
Dim m As Mutex
m = New Mutex(False, appGuid)
If m.WaitOne(0, False) = False Then
MessageBox.Show ("Instance already running")
Return
End If
Application.Run (New Form1())
End Sub
End Class
End Namespace
Using this different piece of code in C# (and the keyword "using") the
method seems to work without problems (and always)
namespace WindowsApplicat ion1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeCompo nent();
}
static string appGuid = "uniquekeyonmym achine";
[STAThread]
static void Main()
{
using (Mutex mutex = new Mutex(false, appGuid))
{
if (!mutex.WaitOne (0, false))
{
MessageBox.Show ("Instance already running");
return;
}
Application.Run (new Form1());
}
}
}
}
What do you think can be the problem? Some people suggested that the
Garbage Collector could have destroy the mutex object before I tryied
to run another instance of the program, but the call to Application.Run
is a blocking one, isn't it? So the local object m should live until
the end of the program, right?
Thank you in advance for your help.
Cold 1 2063
Hello cold80,
This works fine:
Imports System
Imports System.Threadin g
Module Module1
Public Sub Main()
Dim tMutex As Mutex = New Mutex(False, "oggieboogieboo ")
If Not tMutex.WaitOne( 0, False) Then
MsgBox("This is a single-instance app, chedarhead.")
Return
End If
Application.Run (New Form1)
tMutex.ReleaseM utex()
tMutex = Nothing
End Sub
End Module
Also, be aware in VB you must set the startup form to "SUb Main()" in the
project properties. In VS05 this means unchecking the "Use Application Framework"
box first.
-Boo
I'm trying to check in my application if another instance of it is
already running. I found many code snippets on the net that make use
of a named mutex to do this check, but I can't make it work on visual
basic. Actually, it works sometimes and sometimes not. The code I'm
trying is:
Namespace WindowsApplicat ion2
Public Class Form1
Inherits Form
Public Sub New()
End Sub
Private Shared appGuid As String = "uniquekeyonmym achine"
Public Shared Sub Main()
Dim m As Mutex
m = New Mutex(False, appGuid)
If m.WaitOne(0, False) = False Then
MessageBox.Show ("Instance already running")
Return
End If
Application.Run (New Form1())
End Sub
End Class
End Namespace
Using this different piece of code in C# (and the keyword "using") the
method seems to work without problems (and always)
namespace WindowsApplicat ion1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeCompo nent();
}
static string appGuid = "uniquekeyonmym achine";
[STAThread]
static void Main()
{
using (Mutex mutex = new Mutex(false, appGuid))
{
if (!mutex.WaitOne (0, false))
{
MessageBox.Show ("Instance already running");
return;
}
Application.Run (new Form1());
}
}
}
}
What do you think can be the problem? Some people suggested that the
Garbage Collector could have destroy the mutex object before I tryied
to run another instance of the program, but the call to
Application.Run is a blocking one, isn't it? So the local object m
should live until the end of the program, right?
Thank you in advance for your help.
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already running. I found many code snippets on the net that make use of
a named mutex to do this check, but I can't make it work on visual
basic. Actually, it works sometimes and sometimes not. The code I'm
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