Check Email And Mobile Number Availibility exist in database in asp.net

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Data.SqlClient;

using System.Data;

using System.Configuration;

public partial class Default2 : System.Web.UI.Page

{

    protected void Page_Load(object sender, EventArgs e)

    {

    }

    protected void Button1_Click(object sender, EventArgs e)

    {

        SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["conn"].ConnectionString);

        con.Open();

        SqlCommand cmd = new SqlCommand("select email,Mno from GenDetails where email LIKE @email AND Mno LIKE @Mno", con);

        cmd.Parameters.AddWithValue("@email", "'%" + TextBox1.Text + "%'");

        cmd.Parameters.AddWithValue("@Mno", "'%" + TextBox2.Text + "%'");

        cmd.ExecuteNonQuery();

        con.Close();

    }

    protected void TextBox1_TextChanged(object sender, EventArgs e)

    {

        if (!string.IsNullOrEmpty(TextBox1.Text))

        {

            SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["conn"].ConnectionString);

            con.Open();

            SqlCommand cmd = new SqlCommand("select email from GenDetails where email=@email", con);

            cmd.Parameters.AddWithValue("@email", TextBox1.Text);

            SqlDataReader dr = cmd.ExecuteReader();

            if (dr.HasRows)

            {

                Label1.Text = "email id already exists";

            }

            con.Close();

        }

    }

    protected void TextBox2_TextChanged(object sender, EventArgs e)

    {

        if (!string.IsNullOrEmpty(TextBox2.Text))

        {

            SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["conn"].ConnectionString);

            con.Open();

            SqlCommand cmd = new SqlCommand("select MNo from GenDetails where Mno=@Mno", con);

            cmd.Parameters.AddWithValue("@MNo", TextBox2.Text);

            SqlDataReader dr = cmd.ExecuteReader();

            if (dr.HasRows)

            {

                Label2.Text = "Mobile No already exists";

            }

            con.Close();

        }

    }

}