ติดตรงเงื่อนไข เรื่องเวลา ช่วยดูให้หน่อยครับ ผมทำ Dropdownlist 3อัน ติดตรงที่เงื่อนไข ถ้าเลือก วัน/เดือน/ปี

Imports System.data
Imports System.IO
Imports System.Data.SqlClient
Partial Class Default4
    Inherits System.Web.UI.Page
    Public Sub GenerateYear(ByVal NextYear As Integer)
        Dim ThisYear As Integer = Date.Now().Year
        Dim dt As DataTable = New DataTable("GenerateYear")
        Dim dtc As DataColumn
        Dim dtr As DataRow
        dtc = New DataColumn()
        dtc.DataType = System.Type.GetType("System.Int64")
        dtc.ColumnName = "GenYear"
        dt.Columns.Add(dtc)
        For i As Integer = ThisYear To NextYear
            dtr = dt.NewRow()
            dtr(0) = i
            dt.Rows.Add(dtr)
        Next
        Me.ddlYear.DataSource = dt
        Me.ddlYear.DataBind()
    End Sub
    Public Sub GenerateMonth()
        Dim dt As DataTable = New DataTable("GenerateMonth")
        Dim dtc As DataColumn
        Dim dtr As DataRow
        dtc = New DataColumn()
        dtc.DataType = System.Type.GetType("System.Int64")
        dtc.ColumnName = "GenMonth"
        dt.Columns.Add(dtc)
        For i As Integer = 1 To 12
            dtr = dt.NewRow()
            dtr(0) = i
            dt.Rows.Add(dtr)
        Next
        Me.ddlMonth.DataSource = dt
        Me.ddlMonth.DataBind()
    End Sub
    Public Sub GenerateDay(ByVal TotalDay As Integer)
        Dim dt As DataTable = New DataTable("GenerateDay")
        Dim dtc As DataColumn
        Dim dtr As DataRow
        dtc = New DataColumn()
        dtc.DataType = System.Type.GetType("System.Int64")
        dtc.ColumnName = "GenDay"
        dt.Columns.Add(dtc)
        For i As Integer = 1 To TotalDay
            dtr = dt.NewRow()
            dtr(0) = i
            dt.Rows.Add(dtr)
        Next
        Me.ddlDay.DataSource = dt
        Me.ddlDay.DataBind()
    End Sub
    Protected Sub ddlMonth_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ddlMonth.SelectedIndexChanged
        GenerateDay(Date.DaysInMonth(Me.ddlYear.SelectedValue, Me.ddlMonth.SelectedValue))
    End Sub
    Protected Sub ddlYear_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ddlYear.SelectedIndexChanged
        GenerateDay(Date.DaysInMonth(Me.ddlYear.SelectedValue, Me.ddlMonth.SelectedValue))
    End Sub
    Protected Sub ddlDay_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ddlDay.SelectedIndexChanged
        Me.lblSeleceDate.Text = _
        Me.ddlDay.SelectedItem.Text & "/" _
        & Me.ddlMonth.SelectedItem.Text & "/" _
        & Me.ddlYear.SelectedItem.Text
    End Sub
    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        If Not Me.Page.IsPostBack Then
            Dim DateNow As Date
            DateNow = Date.Now()
            GenerateDay(Date.DaysInMonth(DateNow.Year, DateNow.Month))
            GenerateMonth()
            GenerateYear(2020)
            Me.ddlDay.SelectedValue = DateNow.Day
            Me.ddlMonth.SelectedValue = DateNow.Month
            Me.ddlYear.SelectedValue = DateNow.Year
        End If
    End Sub
    Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
        Label1.Text = ""
        Dim connection As String = "Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\Database.mdf;Integrated Security=True;User Instance=True"
        Dim conn As New SqlConnection(connection)
        Try
            conn.Open()
            Dim comm As String = "INSERT INTO CH (CH_IN) "
            comm &= " VALUES ('" & lblSeleceDate.Text & "')"
            Dim command As New SqlCommand(comm, conn)
            command.ExecuteNonQuery()
            conn.Close()
            Response.Redirect("Default2.aspx")
        Catch ex As Exception
            Label1.Text = "พบปัญหาเกี่ยวกับข้อมูลโปรดตรวจสอบ"
        End Try
    End Sub
End Class