ASP.Net รบกวนขอคำสั่งที่ใช้ DropDownList ดึงข้อมูลจาก daatabase มาโชว์ใน textBox หน่อยคับ

Imports System.Text
Imports System.Text.StringBuilder
Imports System.IO
Imports System.Drawing

Public Class CarDetail
    Inherits System.Web.UI.Page
    Dim conn As New dbConn
    Dim fileName As String = "Brand_report.xls"

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        System.Threading.Thread.CurrentThread.CurrentCulture = New System.Globalization.CultureInfo("en-US", False)
        If Not IsPostBack Then
            LoadDDL()
            LoadData()


        End If
        PnlBrand.Visible = False
        pnlAdd.Visible = True
        pnlUpdate.Visible = False
        PnlDelect.Visible = False

    End Sub

    Public Sub LoadData()
        GridView1.DataSource = conn.GetDataTable("Select BrandName as ยี่ห้อ From CarBrand", "CarBrand")
        GridView1.DataBind()

    End Sub

    Public Sub LoadDDL()
        ddlDeleteBrand.DataSource = conn.GetDataTable("Select BrandName From CarBrand", "brand")
        ddlDeleteBrand.DataTextField = "BrandName"
        ddlDeleteBrand.DataValueField = "BrandName"
        ddlDeleteBrand.DataBind()

        ddlUpdateBrand.DataSource = conn.GetDataTable("Select BrandName From CarBrand", "brand")
        ddlUpdateBrand.DataTextField = "BrandName"
        ddlUpdateBrand.DataValueField = "BrandName"
        ddlUpdateBrand.DataBind()

    End Sub

    Protected Sub btnBrandFucntion_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnBrandFucntion.Click
        If ddlBrandFunction.SelectedIndex = 0 Then
            lblFunctionStatus.Text = "Please Select Function"
            pnlFunction.Visible = True
        ElseIf ddlBrandFunction.SelectedIndex = 1 Then
            PnlBrand.Visible = True
            pnlBrandData.Visible = False
            pnlAdd.Visible = True
            pnlUpdate.Visible = False
            PnlDelect.Visible = False
        ElseIf ddlBrandFunction.SelectedIndex = 2 Then
            PnlBrand.Visible = True
            pnlBrandData.Visible = False
            pnlAdd.Visible = False
            pnlUpdate.Visible = True

            TxtUpDateBrand.Text = ""
            PnlDelect.Visible = False
        ElseIf ddlBrandFunction.SelectedIndex = 3 Then
            PnlBrand.Visible = True
            pnlBrandData.Visible = False
            pnlAdd.Visible = False
            pnlUpdate.Visible = False
            PnlDelect.Visible = True
        End If

    End Sub

    Protected Sub btnCommand_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnCommand.Click
        If ddlMode.SelectedIndex = 0 Then
            lblModetatus.Text = "Please Select Mode"
        ElseIf ddlMode.SelectedIndex = 1 Then
            lblModetatus.Text = "Brand mode"
            PnlBrand.Visible = True
            pnlBrandData.Visible = True
            pnlUpdate.Visible = False
            PnlDelect.Visible = False
            pnlAdd.Visible = False
        ElseIf ddlMode.SelectedIndex = 2 Then
            lblModetatus.Text = "Model mode"

        End If
    End Sub


    
End Class