login page

public partial class _Default : System.Web.UI.Page
    {
        SqlConnection con = new SqlConnection(@"Data Source = A\SQLEXPRESS;Initial Catalog=bank;Integrated Security = True");
        SqlDataAdapter ada;
        DataSet ds;
        protected void Page_Load(object sender, EventArgs e)
        {
            
        }

        protected void btnlogin_Click(object sender, EventArgs e)
        {
            try
                {

                string struname = txtusername.Text;
                string strpwd = txtpwd.Text;
                ds = new DataSet();
                ada = new SqlDataAdapter("SELECT * FROM users WHERE Username = '" + struname + "' and Password = '" + strpwd + "'", con);
                ada.Fill(ds, "users");
                if (Convert.ToBoolean(ds.Tables["users"].Rows[0]["IsAdmin"].ToString() == "True"))
                {
//This page redirects to Admin Page//
                    Response.Redirect("AdminScreen.aspx");
                }
                else if (ds.Tables[0].Rows.Count == 0)
                {
                    Response.Write("<script>alert('Please check the Username and Password')</script>");
                    clearcontrols();
                    txtusername.Focus();
                }
                else
                {
// This webpage redirects to the User Page//
                    Session["Id"] = ds.Tables[0].Rows[0][0].ToString();
                    Session["username"] = ds.Tables[0].Rows[0][1].ToString();
                    
                }
            }
            catch
            {
                Response.Write("<script>alert('Please check the Username and Password')</script>");
            }
            

        }
        public void clearcontrols()
        {
            txtusername.Text = "";
            txtpwd.Text = "";
        }
    }
}