easy way to check if a form is already open

[TonyVR4]

Is there any way to check if a form is already open and if so set the focus to it instead of opening another instance of that form ?

Thanks
--
Tony

[Pirate]

'Class member variable 
    Dim frm2 As New Form2
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        If Not frm2 Is Nothing Then
            frm2.Show()
            frm2.Activate()
        End If
    End Sub

[Carnifex]

You also need to check if the form has been closed (disposed) as it will not be nothing, and will give you an object disposed exception if you try to open it.

Heres an edit to Pirates code.

If Not myForm Is Nothing Then
        'Check if the form is still considered created
        If myForm.Created = True Then
                 myForm.Show()
                 myForm.Activate
        End If
End If

[TonyVR4]

Awesome. That looks just like the ticket.

I will give it a shot
Thanks
Tony

[Carnifex]

The other option would be to set myForm to nothing in a form closed event.

[TonyVR4]

I tried that and when I click on the button to open my new form, it doesn't do anything.

My form is called

Here is the code behind the click event of the button to open my form:

Dim AddNewShoppingForm As New frmAddNewShopping
If AddNewShoppingForm Is Nothing Then
If AddNewShoppingForm.Created = True Then
AddNewShoppingForm.Show()
AddNewShoppingForm.Activate()
End If
End If

[Pirate]

Originally posted by Pirate

'Class member variable 
    Dim frm2 As New Form2
 
    Private Sub Button1_Click(ByVal sender As System.Object, 
ByVal e As System.EventArgs) Handles Button1.Click
        If Not frm2 Is Nothing Then
            frm2.Show()
            frm2.Activate()
        End If
    End Sub

Did you try this way . It works fine for me .

[Carnifex]

If you want a new form to be created if it isn't then modify the code to this.

If Not myForm Is Nothing Then
        'Check if the form is still considered created
        If myForm.Created = True Then
                 myForm.Show()
                 myForm.Activate
        Else
                 myForm = New myForm
                 myForm.Show
        End If
Else
        myForm = New myForm
        myForm.Show
End If

Basically creates a new instance of the form if the old one doesn't exist anymore/was never created.

[TonyVR4]

Ah that actually works.

I found the problem. I had to move the dim statement for the new form to the declatations and it now works fine.

I had the dim statement before in the click event of the button and it didn't work there.

Thanks all
Tony

[Pirate]

Originally posted by Pirate

'Class member variable 
    Dim frm2 As New Form2
 
    Private Sub Button1_Click(ByVal sender As System.Object, 
ByVal e As System.EventArgs) Handles Button1.Click
        If Not frm2 Is Nothing Then
            frm2.Show()
            frm2.Activate()
        End If
    End Sub

If you read carefully , you'd have solved it (class member variable)