无法将打开的表单带到前台/焦点vb.net

Question

Hi i have five forms and i want to open a form only if it's not open, if it's open bring to front or focus. i have tried using BringToFront , Show and TopMost but nothing works.

If Not Application.OpenForms.OfType(Of StudentRegistrationFrm).Any Then
        StudentRegistrationFrm.ShowDialog()
    Else
        StudentRegistrationFrm.BringToFront()
        'Me.SendToBack()
End If

Answer 1

I have solved it by closing the current form.

 If Not Application.OpenForms.OfType(Of StudentRegistrationFrm).Any Then
        StudentRegistrationFrm.Show()
    Else
        Me.Close()
    End If
   Private Sub StudentInformationToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles StudentInformationToolStripMenuItem.Click
    Dim studentReg As StudentInfoFrm = New StudentInfoFrm
    studentReg.Show()
    Me.Close()
 End Sub