怎样在一个下拉菜单中选择年,日历控件就显示那年的月份

Private Sub Combo1_Click()
Select Case Combo1.ListIndex
Case 0: For i = 28 To 30
Label4(i).Visible = True
Next i
Case 1:
If Val(Combo2.Text) Mod 4 = 0 Then
For i = 29 To 30
Label4(i).Visible = False
Next i
Label4(28).Visible = True
Else
For i = 28 To 30
Label4(i).Visible = False
Next i
End If
Case 2:
For i = 28 To 30
Label4(i).Visible = True
Next i
Case 3:
For i = 27 To 29
Label4(i).Visible = True
Next i
Case 4:
For i = 28 To 30
Label4(i).Visible = True
Next i
Case 5:
For i = 27 To 29
Label4(i).Visible = True
Next i
Label4(30).Visible = False
Case 6:
For i = 28 To 30
Label4(i).Visible = True
Next i
Case 7:
For i = 28 To 30
Label4(i).Visible = True
Next i
Case 8:
For i = 27 To 29
Label4(i).Visible = True
Next i
Label4(30).Visible = False
Case 9