C# นำข้อมูลจาก Database มาแสดงใน Textbox ไม่ยอมแสดง ไม่มี Error

<%@ Page Title="Home Page" Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="false"
    CodeBehind="Default.aspx.cs" Inherits="_Default" %>

<asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent"></asp:Content>
<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">
        <strong>Welcome to SYSTEM!
    </strong>
    <p class="style1">
        <strong>ระบบเปลี่ยนและสำรองแผนงาน.
    </strong>
    </p>
    <br/>
    <form action= "Default.aspx">
            <div class="style2">
            &nbsp;&nbsp;&nbsp;<asp:Label 
            ID="Label1" runat="server" style="font-weight: 700" Text="เลขที่หนังสือ : "></asp:Label>
                &nbsp;<asp:TextBox ID="SearchTxtb" runat="server" style="font-size: small"></asp:TextBox>
        &nbsp;&nbsp;&nbsp;
                <asp:Button ID="SearchBtn" runat="server" Text="Search" 
                onclick="SearchBtn_Click" />
                <br />
                <br />
                <asp:Label ID="lblCheck" runat="server" Text="Label" Visible="False"></asp:Label>
                <br />
                ********************************************</div>
     </form>
                <br />    
    <form id="Current_Programme">
        <asp:Panel id="pnlProgramme" runat="server">
         <table width="605" border="0">
            <tbody>
                .
                .
                .
            </tbody>
         </table>
        </asp:Panel>
    </form>    
</asp:Content>

public partial class _Default : System.Web.UI.Page
    {
        SqlConnection objConn = new SqlConnection();
        SqlCommand objCmd = new SqlCommand();
        String strConnString, strSQL;
        
        protected void Page_Load(object sender, EventArgs e) 
        {
            this.pnlProgramme.Visible = false;
            strConnString = "Server=localhost;UID=sa;PASSWORD=0000;database=mydatabase;Max Pool Size=400;Connect Timeout=600;";
            objConn.ConnectionString = strConnString;
            objConn.Open();
        }
        void ViewData(){
            if (!Page.IsPostBack)
            {

                //Data Table
                DataTable dt = new DataTable();
                String strKeyword = this.SearchTxtb.Text.ToString();
                SqlDataReader myReader = null;
                SqlCommand myCommand = new SqlCommand("select * from Record where RecordID='" + strKeyword + "'", objConn);       
                myReader = myCommand.ExecuteReader();
                while (myReader.Read())
                {
                    this.SearchTxtb.Text = (myReader["RecordID"].ToString());
                    this.txtDateRec.Text = (myReader["[Date-Record]"].ToString());
                    //this.txtDateRev.Text = dt.Rows[0]["[Date-Received]"].ToString();
                    //this.txtExpID.Text = dt.Rows[0]["[Record-Export]"].ToString();
                    //this.txtDateExp.Text = (String)dt.Rows[0]["[Date-RecordExport]"];
                    //this.txtPeriod.Text = dt.Rows[0]["Period"].ToString();
                    //this.txtPlanID.Text = dt.Rows[0]["[Plan]"].ToString();
                    //this.txtCatID.Text = dt.Rows[0]["category"].ToString();
                    //this.txtTexture.Text = dt.Rows[0]["Material"].ToString();
                    //this.txtCost.Text = dt.Rows[0]["Cost"].ToString();
                    //this.txtCons.Text = dt.Rows[0]["Estimatedcost"].ToString();
                }
                objConn.Close();
            }
        }
        void Page_Unload() {
            objConn.Close();
            objConn = null;
        }
        protected void SearchBtn_Click(object sender, EventArgs e)
        {
            this.pnlProgramme.Visible = true;
            ViewData();      
            
        }