beats怎么煲机:急，关于 ASP.NET 的问题

下面这段代码，在运行时，下拉列表不会出到值，这是怎么回事呀？

Dim myddlYear As DropDownList = Page.FindControl("ddlYear")
Dim myddlMonth As DropDownList = Page.FindControl("ddlMonth")
Dim myddlDay As DropDownList = Page.FindControl("ddlDay")
Dim myddlHour As DropDownList = Page.FindControl("ddlHour")

Dim intCounter As Integer
'初始化年份下拉列表
For intCounter = 2006 To 2099
myddlYear.Items.Add(New ListItem(intCounter.ToString, intCounter.ToString))
Next
myddlYear.DataBind()
'初始化月份下拉列表
For intCounter = 1 To 12
myddlMonth.Items.Add(New ListItem(intCounter.ToString, intCounter.ToString))
Next
myddlMonth.DataBind()
'初始化日下拉列表
Select Case myddlMonth.SelectedValue
Case Is = "2"
Dim intYear As Integer = CType(myddlYear.SelectedValue, Integer)
If (intYear / 4 = 0 And intYear / 100 <> 0) Or intYear / 400 = 0 Then
For intCounter = 1 To 29
myddlDay.Items.Add(New ListItem(intCounter.ToString, intCounter.ToString))
Next
Else
For intCounter = 1 To 28
myddlDay.Items.Add(New ListItem(intCounter.ToString, intCounter.ToString))
Next
End If
Case Is = "1", "3", "5", "7", "8", "10", "12"
For intCounter = 1 To 31
myddlDay.Items.Add(New ListItem(intCounter.ToString, intCounter.ToString))
Next
Case Is = "4", "6", "9", "11"
For intCounter = 1 To 30
myddlDay.Items.Add(New ListItem(intCounter.ToString, intCounter.ToString))
Next
Case Else
'其它情况
End Select
myddlDay.DataBind()

'初始化小时
For intCounter = 0 To 24
myddlHour.Items.Add(New ListItem(intCounter.ToString, intCounter.ToString))
Next
myddlHour.DataBind()