Check if form is Opened

Question

I give this question for more knowledge. How can I know if the form is Opened in my application or not, in order not to open it again I mean not to create an instance of the

Answer 1

you can try this

Dim formText As String
Dim prevText As String

 Private Sub OpenForm(ByVal frm As Windows.Forms.Form)
        formText = frm.Text
        If formText = prevText Then Exit Sub
        CloseForms()
        ' Make it a child of this MDI form before showing it.
        frm.MdiParent = Me
        frm.Show()
        frm.Location = New Point(0, 0)
        prevText = formText
    End Sub

    Private Sub CloseForms()
        For Each ChildForm As Form In Me.MdiChildren
            ChildForm.Close()
        Next
    End Sub

    Private Sub NewToolStripButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles PayablesToolStripMenuItem.Click
            OpenForm(frmPayables)
        End Sub