CODE EXAMPLE FOR CSHARP

vb.net center form in screen

Public Shared Sub CenterForm(ByVal frm As Form, Optional ByVal parent As Form = Nothing)
    '' Note: call this from frm's Load event!
    Dim r As Rectangle
    If parent IsNot Nothing Then
        r = parent.RectangleToScreen(parent.ClientRectangle)
    Else
        r = Screen.FromPoint(frm.Location).WorkingArea
    End If

    Dim x = r.Left + (r.Width - frm.Width)  2
    Dim y = r.Top + (r.Height - frm.Height)  2
    frm.Location = New Point(x, y)
End Sub