ติดบรรทัดที่ ไฮไลท์ สีเหลืองครับรบกวนช่วยดูหน่อยครับ ขอบคุณครับ

    public partial class Window1 : Window
    {
        SqlConnection Conn = new SqlConnection();

        private void Window1_Load(object sender, EventArgs e)
        {
            string strConn = Conn.ConnectionString;

            if (Conn.State == ConnectionState.Open)
            {
                Conn.Close();
            }

            Conn.ConnectionString = strConn;
            Conn.Close();
        }
        private void btnSubmitMM_Click(object sender, RoutedEventArgs e)
        {
                StringBuilder sb = new StringBuilder();
                sb.Append("SELECT MemberUsername,MemberPassword FROM MemberUsername");
                sb.Append(" WHERE (MemberUsername=@UserName)");
                sb.Append(" AND (MemberPassword=@PassWord)");

                SqlParameter UserName = new SqlParameter("UserName", SqlDbType.NVarChar);
                SqlParameter PassWord = new SqlParameter("PassWord", SqlDbType.NVarChar);

                string sqlLogin;
                sqlLogin = sb.ToString();

                SqlCommand com = new SqlCommand();
                SqlDataReader dr;

                com.CommandType = CommandType.Text;
                com.CommandText = sqlLogin;
                com.Connection = Conn;
                com.Parameters.Add(UserName).Value = usernameTextBoxMM.Text;
                com.Parameters.Add(PassWord).Value = passwordTextBoxMM.Password;

                dr = com.ExecuteReader();

                if (dr.HasRows)
                {
                    //frmMain fMain = new frmMain();
                    //fMain.Show();
                    //this.Hide();
                    MessageBox.Show("Complete", "Process Report", MessageBoxButton.OK, MessageBoxImage.Exclamation);

                }
                else {
                    MessageBox.Show("Username Or Password InValid", "Process Report", MessageBoxButton.OK, MessageBoxImage.Exclamation);
                    usernameTextBoxMM.Text = null;
                    usernameTextBoxMM.Focus();
                    passwordTextBoxMM.Password = null;
                }
                dr.Close();
                dr.Dispose();
            }
        }

    }