C# 调用Lotus Notes发送邮件

As title.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using Domino;

namespace NetUseNotes
{
    public partial class Form1 : Form
    {
        NotesSession NSession;
        NotesDatabase NDataBase;
        
        public Form1()
        {
            InitializeComponent();
        }
        private void btnsend_Click(object sender, EventArgs e)
        {
            try
            {
                if (NSession != null)
                {
                    NotesDocument NDocument = NDataBase.CreateDocument();
                    NDocument.ReplaceItemValue("Form", "Memo");
                    
                    NDocument.ReplaceItemValue("SendTo", txtToUser.Text);                   
                    NDocument.ReplaceItemValue("Subject", txtSubject.Text);                     
                    NotesRichTextItem rt = NDocument.CreateRichTextItem("Body");
                    rt.AppendText(txtBody.Text);                    
                 
                    object obj = NDocument.GetItemValue("SendTo");
                    NDocument.Send(false, ref obj);
                    NDocument = null;
                    MessageBox.Show("Successfully!");
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show("Error:" + ex.Message);
            }
        } 

        private void Form1_Load(object sender, EventArgs e)
        {            
            NSession = new NotesSession();
            NSession.Initialize("UserName");            
            NDataBase = NSession.GetDatabase("Notes Server", "names.nsf", false); 
        }         
    }
}