how to check if form is open

[purplehaze1]

Is there a way to check if form is open?
If so, how to close it.
For example, I have formA & formB.
I want to open formB from FormA if formB is not
open. If it is open, then close it. Thanks.

 

[terpy]

I assume you have already dimmed the form. Once you do that, the form exists in memory; it just isn't visible to the user. However, certain properties of the form are not initialized when you dim it, specifically its position on the screen. So one thing you could do (and I sure hope someone else has something a bit more elegant) is to examine the DesktopBounds of the form. As long as you don't display your form in the topmost left position (0,0), this will work:

[blue]dim db as System.Drawing.Rectangle = frmMine.DesktopBounds
If db.Y > 0 Then frmMine.Close()[/blue]

In addition to Y, X, Left, and Top are also set to zero. Once you show the form, those properties are most likely non-zero. To be safe, you should test for more than just db.Y = 0.

terpy

 

[levogiro]

hi,

i'm developing an MDI application and had the same problem...i'm not sure if i found the best solution, but here it is...

    Dim fUsuario As frmUsuario

    Private Sub mniUsuario_Click(ByVal sender As 
                        System.Object, 
                        ByVal e As System.EventArgs) 
                Handles mnuUsuario.Click

        If Not fUsuario Is Nothing Then
            fUsuario.Close()
        End If

        fUsuario = New frmUsuario
        fUsuario.MdiParent = Me
        fUsuario.Show()

    End Sub

i hope it helps.