มันไม่ตรวจสอบ user แล้วไม่ลงฐานข้อมูล แก้ไง ใครมีวิธีแนะนำหน่อย

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.Configuration;
using System.Data.SqlClient;
using System.Text;

public partial class registermember : System.Web.UI.Page
{
    //private Sub autoMember_ID();

    private string strConn;
    private string strSql;
    private SqlCommand cmd;
    private SqlConnection conn;
    SqlConnection Conn = new SqlConnection();
    SqlCommand Cmd = new SqlCommand();
    string sqlStr;
    SqlDataReader dr;






    protected void Page_Load(object sender, EventArgs e)
    {
        strConn = WebConfigurationManager.ConnectionStrings["casio1"].ConnectionString;
        Conn.ConnectionString = strConn;
        Conn.Open();
        this.Label3.Visible = true;


    }
    protected void bsave_Click(object sender, EventArgs e)
    {
        string strSQL, strConn = "Data Source = COMPUTER-PC;Initial Catalog=Casio1;Integrated Security=true";
        Conn = new SqlConnection();
        if (Conn.State == ConnectionState.Open)
        {
            this.Label3.Text = "ผิดพลาดมีปัญหาในการเชื่อมต่อฐานข้อมูล";
            //label1.Show("ผิดพลาดมีปัญหาในการเชื่อมต่อฐานข้อมูล", "ระบบผิดพลาด");

        }
        else
        {
            Conn.ConnectionString = strConn;
            Conn.Open();
            DataSet dat = new DataSet();
            SqlCommand cmd;
            int intNumRows = 0;

            strSQL = "SELECT COUNT (user_mem)  FROM  Member WHERE user_mem ='" + this.tuser.Text + "'";
            cmd = new SqlCommand(strSQL, Conn);
            intNumRows = Convert.ToInt32(cmd.ExecuteScalar());

            if (intNumRows > 0)
            {
                this.pnlAdd.Visible = false;
                this.Label3.Visible = true;
                this.Label3.Text = "Username already exists.";
            }
            else
            {



                if ((RadioButton1.Checked == true))
                {

                    sqlStr = "INSERT INTO Member (user_mem,password_mem,idcard_mem,name_mem,surname_mem,brith_mem,gender_mem) " + " VALUES " + " ('" + this.tuser.Text + "','" + this.tpass.Text + "','" + this.tcard.Text + "','" + this.tname.Text + "','" + this.tsurname.Text + "','" + this.tbirth.Text + "','" + this.RadioButton1.Text + "')";
                }
                else
                {
                    sqlStr = "INSERT INTO Member (user_mem,password_mem,idcard_mem,name_mem,surname_mem,brith_mem,gender_mem,career_mem) " + " VALUES " + " ('" + this.tuser.Text + "','" + this.tpass.Text + "','" + this.tcard.Text + "','" + this.tname.Text + "','" + this.tsurname.Text + "','" + this.tbirth.Text + "','" + this.RadioButton2.Text + "','" + this.ddl_career.Text + "')";
                }
                //sqlStr = "INSERT INTO member(user_mem,password_mem,date_mem, , address_mem, province_mem, postal_mem, phone_mem, email_mem)" + " VALUES " + "('" + this.tuser.Text+ "','" + this.tpass.Text+ "','" + this.tcard.Text+ "','" + this.ldate.Text+ "','" + this.tb_address.Text+ "',  '" + this.tbpostal.Text+ "','" + this.tbphone.Text+ "','" + this.temail.Text+ "')";




                //cmd.Parameters.Add("@province_mem", SqlDbType.VarChar).Value = ddlprovice.Text.Trim();



                //if (RadioButton1.Checked == true)
                //{
                //    cmd.Parameters.Add("@gender_mem", SqlDbType.VarChar).Value = "ชาย";
                //}

                //else 
                //{
                //    cmd.Parameters.Add("@gender_mem", SqlDbType.VarChar).Value = "หญิง";
                //}  

                Cmd = new SqlCommand();

                {
                    Cmd.Connection = Conn;
                    Cmd.CommandText = sqlStr;
                    Cmd.CommandType = CommandType.Text;
                }

                this.pnlAdd.Visible = false;
                try
                {
                    Cmd.ExecuteNonQuery();
                    this.Label3.Text = "Register Sucessful.";
                    this.Label3.Visible = true;
                }
                catch (Exception ex)
                {
                    this.Label3.Visible = true;
                    this.Label3.Text = "Cannot Register : Error (" + ex.Message + ")";
                }
            }
            Conn.Close();
            Conn = null;
        }
    }
}