关于登录有关问题

关于登录问题；

C# code

 public partial class login : System.Web.UI.Page    {        public static string strCon = "server= .; uid=sa; pwd=sa; database=hager";        protected void Page_Load(object sender, EventArgs e)        {        }        protected void ImageButton1_Click(object sender, ImageClickEventArgs e)        {            string sqlsel = "select count(*) from tUser where fCode='" + TextBox1.Text + " and fPassword='" + TextBox2.Text + "''";            SqlConnection con = new SqlConnection(strCon);            con.Open();            SqlCommand com = new SqlCommand(sqlsel, con);                                 if (Convert.ToInt32(com.ExecuteScalar())> 0)            {                RegisterStartupScript("", "<script>alert('登录成功！')</script>");            }            else            {                RegisterStartupScript("", "<script>alert('登录失败！')</script>");            }        }    }

C# code

" and fPassword='" + TextBox2.Text + "''";