Is an Instance of a form "open"

Hello All,

I'm back again with yet another small question...

How can I tell if an instance of one of my forms is already open? I didn't see any kind of "status" property...

For the sake of simplicity in answering, let's assume my form instance is called MyForm and was initiated at the start of my application...

VB Code:

Public MyForm as New frmMyForm

I just need to know if I have opened it (MyForm.Show) or not...

Thanks in advance,

Squirrelly1 :D

like this? if not, sorry...

VB Code:

Dim f As Form
      For Each f In Me.MdiChildren
         If f.Text.Equals("Form2") Then
            f.Select()
            Exit Sub
         End If
      Next
      f = New Form2()
      f.Show()
      f.MdiParent = Me

Hi, Squirrelly :)
If you are sure your form was declared and you only want to know if it is displayed, perhaps you can use something like this:

If MyForm.Visible = True Then
MsgBox("Visible")
End If

Form.Show is the same of Form.Visible=True, and Form.Hide is the same of Form.Visible=False

If it's possible the Form was been closed you need to check that, but, if it's not possible, it should be sufficient....I think and hope
:bigyello:

Alan,

Thanks for the reply, but I'm not sure if this would work for me because I'm using a Tab/Panel senario for my form display (it's really quite neat actually).


Alextyx,

Here to save the day again I suppose... :p As I told Alan, I'm using a Tab/Panel senario to display my forms... I'll have to do a little testing to see if switching tabs actually makes the forms or panels visible... I think it would be the panels, but the panels, as you probably know are just the parents for my forms, so this may still work.... I'll just have to try ;)


Thanks again,

Squirrelly1 :wave:

Man Alextyx, you make me feel like a slacker with my mere 615 posts since 01 and you having over 100 since March 04... :p

You can use a mutex to do this:

VB Code:

Private blnout As Boolean
    Private objMut As New System.Threading.Mutex(True, "frmProgress", blnout)
 
 
    Private Sub frmProgressbar_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        'Create a mutex to see if there is already an instance of my app running
 
 
        If blnOut = False Then
            Me.Close()
 
        End If
    End Sub
 
    Private Sub frmProgressbar_Closing(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles MyBase.Closing
        objMut.Close()
    End Sub