怎样设计出能算出你出生时是星期几

代码如下：

Private Sub Command1_Click()
Dim Year As Integer
Dim Month As Integer
Dim Day As Integer
Dim Birthday As Date
Dim N As Integer
Year = Int(Val(Text1.Text))
Month = Int(Val(Text2.Text))
Day = Int(Val(Text3.Text))
Birthday = DateSerial(Year, Month, Day)
N = Weekday(Birthday)
Label6.Caption = MyWeekdayName(N)
End Sub
Private Function MyWeekdayName(N As Integer) As String
Select Case N
    Case 1
        MyWeekdayName = "星期天"
    Case 2
        MyWeekdayName = "星期一"
    Case 3
        MyWeekdayName = "星期二"
    Case 4
        MyWeekdayName = "星期三"
    Case 5
        MyWeekdayName = "星期四"
    Case 6
        MyWeekdayName = "星期五"
    Case 7
        MyWeekdayName = "星期六"
    End Select
End Function