login code

Question

protected void btnlogin_Click(object sender, EventArgs e)
    {
        string strcon = ConfigurationManager.ConnectionStrings["pranjalConnectionString"].ToString();
        SqlConnection con = new SqlConnection(strcon);
        con.Open();


        string email = txtEmailid.Text.Trim();
        string passwd = txtPassword.Text.Trim();



        string sql = "Select Email,password from reg_vidyatbl where Email='" + txtEmailid+ "'and password='" + txtPassword + "'";

        SqlCommand cmd = new SqlCommand(sql, con);
       
        cmd.ExecuteNonQuery();


        SqlDataAdapter da = new SqlDataAdapter(cmd);

        DataSet dt = new DataSet();
        da.Fill(dt);
        if (dt.Tables[0].Rows.Count > 0)
        {

            Response.Redirect("home.aspx");

        }
        else
        {

            lblerrorlog.Text = "invalid usernane or password";
        }
   
this is my login code but it is not working properly,im directly getting error msg.control is not going insid the if codition.let me know if i ha made any mistake