ถามเกี่ยวกับ asp.net ผมจะทำการ update profile โดย ดึงค่าจาก datbase โชว์ใน textbox ทั้งหมด

public partial class Profilesinfo : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

        if (IsPostBack == false)
        {
           
        }

        TextBox1.Text = Session["UserNameCustomer"].ToString();

        string strConn;
        strConn = " Data Source= CODENAME\\SQLEXPRESS ;Database=master; User ID=sa;Password=12345";

        SqlConnection Conn = new SqlConnection(strConn);
        Conn.Open();


        string sqlString = ("SELECT  Password,FirstName,LastName,[E-mail],Phone,BirthDay,BirthMonth,BirthYear,Street,State,City,Zipcode,Country FROM Customer Where UserName ='" + Session["UserNameCustomer"].ToString() + "'");


        DatabaseManager dbManager = new DatabaseManager("master");

        DataTable result = dbManager.ReadData(sqlString);

        TextBox2.Text = result.Rows[0]["Password"].ToString();
        TextBox3.Text = result.Rows[0]["FirstName"].ToString();
        TextBox12.Text = result.Rows[0]["LastName"].ToString();
        TextBox4.Text = result.Rows[0]["E-Mail"].ToString();
        TextBox5.Text = result.Rows[0]["Phone"].ToString();
        DropDownList1.Text = result.Rows[0]["BirthDay"].ToString();
        DropDownList2.Text = result.Rows[0]["BirthMonth"].ToString();
        DropDownList3.Text = result.Rows[0]["BirthYear"].ToString();
        TextBox6.Text = result.Rows[0]["Street"].ToString();
        TextBox8.Text = result.Rows[0]["State"].ToString();
        TextBox9.Text = result.Rows[0]["City"].ToString();
        TextBox10.Text = result.Rows[0]["Zipcode"].ToString();
        TextBox11.Text = result.Rows[0]["Country"].ToString();
      
    }



    protected void Button1_Click1(object sender, EventArgs e)
    {
           if (TextBox1.Text == "" || TextBox2.Text == "" || TextBox3.Text == "" || TextBox4.Text == "" || TextBox5.Text == "" || TextBox6.Text == "" || DropDownList1.Text == "Null" || DropDownList2.Text == "Null" || DropDownList3.Text == "Null" || TextBox8.Text == "" || TextBox9.Text == "" || TextBox10.Text == "" || TextBox11.Text == "" || TextBox12.Text == "")
        {
            MessageBox.Show("Please input all of information");
        }

        else
        {
  
            int flag = 0;
            for (int a = 0; a < TextBox4.Text.Length; a++)
                if (TextBox4.Text[a] == '@')
                {
                    flag++;

                }

            if (flag == 0 || !Char.IsLetter(TextBox4.Text[0]) || !Char.IsLetter(TextBox4.Text[TextBox4.Text.Length - 1]))
            {
                MessageBox.Show("Please correct syntax [email protected]");
            }

            else
            {
                int ff = 0;
                for (int i = 0; i < TextBox5.Text.Length; i++)

                    if (Char.IsDigit(TextBox5.Text[i]))
                    {
                        ff++;
                    }
                if (ff < TextBox5.Text.Length)
                {
                    MessageBox.Show("Please input only number of Telephone");
                }
                else
                {
                    int ffa = 0;
                    for (int g = 0; g < TextBox10.Text.Length; g++)

                        if (Char.IsDigit(TextBox10.Text[g]))
                        {
                            ffa++;
                        }
                    if (ffa < TextBox10.Text.Length)
                    {
                        MessageBox.Show("Please input only number of zipcode");
                    }

                    else
                    {
                   
                        DatabaseManager dbManager1 = new DatabaseManager("master");
                        string sqlString1 = "UPDATE Customer SET Password= '" + TextBox2.Text + "' ,   FirstName = '" + TextBox3.Text + "' , LastName =  '" + TextBox12.Text + "' ,   [E-mail]= '" + TextBox4.Text + "' , Phone=  '" + TextBox5.Text + "' ,  BirthDay = '" + DropDownList1.Text + "' ,  BirthMonth =  '" + DropDownList2.Text + "',  BirthYear =  '" + DropDownList3.Text + "' ,  Street = '" + TextBox6.Text + "' , State =  '" + TextBox8.Text + "' ,  City =  '" + TextBox9.Text + "' ,  Zipcode = '" + TextBox10.Text + "' ,  Country=  '" + TextBox11.Text + "' WHERE UserName = '" + Session["UserNameCustomer"].ToString() + "' ";
                        dbManager1.ExecuteNonQuery(sqlString1);
                        Response.Redirect("~/updateprofile.aspx");


                    }

                }


            }
        }
   
             
    }