you can use dims

Code:
dim itsame as boolean
       Private Sub Form2_LocationChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.LocationChanged
        If Me.Left < (dockable area) Or Me.Left = 0 Then
            Me.Left = 0
me.height = 'yourmdi.height
itsame= true
else
 itsame = false
        End If
if itsame = true then
me.top = 0
end if
    End Sub