is there an easy way to tell if my program is already running

Is there any way to check if another instance of my program is running if a user executes it ?

I would like to warn the user if the program is already running to prevent multiple instances.

I am new to vb.net so any help is greatly appreciated.
Thanks
--
Tony

VB Code:

'Create a new instance of your main form
    Dim MainForm As New Form1()
 
    Private Sub MultiCheck()
        'Get number of processes of you program
        If Process.GetProcessesByName(Process.GetCurrentProcess.ProcessName).Length > 1 Then
            'Ask user if they want to run another copy
        If MessageBox.Show("There is already a copy of this program." & vbCrLf _
            & "Do you want to launch another?.", _
            "Launch another copy of this program?", _
            MessageBoxButtons.YesNo, MessageBoxIcon.Question, _
            MessageBoxDefaultButton.Button1) = DialogResult.No Then
            'If no, then exit the new instance of the program
                Application.Exit()
                Exit Sub
            Else
            'Else run the new program
                MainForm.ShowDialog()
                Exit Sub
            End If
        End If
        'If this is the only one, run it!
        MainForm.ShowDialog()
    End Sub

Btw , there's another way by using :Mutex . Both lead to the same result though .

This looks just the ticket. What is mutex ?

I have never heard of that. All my prior programming had been in VB6. Is it something new to .net ?

Thanks
Tony

didnt they add a property or something in vs2003 that was like the old prevInstance in vb6? or am I thinking of something else?

Quote:

---

Originally posted by TonyVR4
This looks just the ticket. What is mutex ?

I have never heard of that. All my prior programming had been in VB6. Is it something new to .net ?

Thanks
Tony

---

Yes , it's new to .NET . Ex :

http://www.freevbcode.com/ShowCode.asp?ID=5845

Quote:

---

Originally posted by MrPolite
didnt they add a property or something in vs2003 that was like the old prevInstance in vb6? or am I thinking of something else?

---

I don't think so . They added some 'easy' and indirect ways to this . ;)

Quote:

---

Originally posted by Pirate
Yes , it's new to .NET . Ex :

http://www.freevbcode.com/ShowCode.asp?ID=5845

---

It's not something new at all, it existed since the very beggining in the win API

Quote:

---

Originally posted by PT Exorcist
It's not something new at all, it existed since the very beggining in the win API

---

No , it's new to .NET . I mean as managed code . Ofcourse it was based on API . :rolleyes:

I tried this and it sits there for a long time, then I get and error on the line where I do the ShowDialog "Error Creating Window Handle"

Here is the code I put into my form load. My form is called frmMain

Dim MainForm As New frmMain
'Get number of processes of you program
If Process.GetProcessesByName(Process.GetCurrentProcess.ProcessName).Length > 1 Then
MessageBox.Show("There is already a copy of this program running", "", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
'If another instance is running then exit
Application.Exit()
Exit Sub
Else
'Else run the new program
MainForm.ShowDialog()
Exit Sub
End If

Where did you add this code ?

I added it in the beginning of the form load event for my main form

Thanks
Tony

I am trying to get the same information.

In a button's click event on my form I call my PrevInstance function. In that function I have both Pirate's method and the method I found in vb.net help.
Pirates always returns 0. the Help's method always returns -1.

Public Function PrevInstance() As Boolean
MsgBox(Process.GetProcessesByName(Process.GetCurrentProcess.ProcessName).Length)
If UBound(Diagnostics.Process.GetProcessesByName(Diagnostics.Process.GetCurrentProcess.ProcessName)) > 0 Then
Return True
Else
Return False
End If

End Function

Can anyone see the problem?

Thanks,
Robb

I would suggest the using a mutex instead. Its about ten times faster than querying the processes.

http://www.vbforums.com/showthread.p...hreadid=260721