Display a modeless Form but only one

Question

VB2010. I must be missing something because I couldn't find a solution after searching for an hour. What I want to do is simple. In my app I want to display a modeless form so that it is floating while the user can still interact with the main form.

dim f as New frmColors
f.Show(Me)

But I only want one instance of the form at any time. So how can I prevent more than once instance being displayed, and if there is one instance then just give it focus?

Answer 1

Does something like this work for you, if the form is already visible you can not do a Show, you can just do a BringToFront, also you can check to see if the Form has been disposed so you can New up another one.

Public Class Form1
    Dim f As New frmColors

    Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
        If f.IsDisposed Then f = New frmColors 'To handle user closing form
        CheckForm(f)
    End Sub

    Private Sub CheckForm(frm As Form)
        If frm.Visible Then
            frm.BringToFront()
        Else
            frm.Show(Me)
        End If
    End Sub    
End Class

Answer 2

Make your form follow the singleton pattern. I can't vouch for this sample, but from the text it appears to do what you want.