原文地址：http://www.developer.com/net/net/article.php/11087_3373951_1

保存：

 private void btnSave_Click(object sender, System.EventArgs e)
  {
   
   FileStream stream = null;
   SqlConnection conn = null;
   SqlCommand cmd = null;
   try
   {
    richTextBox1.SaveFile( "temp.rtf" );
    stream = new FileStream("temp.rtf", FileMode.Open, FileAccess.Read);
    int size = Convert.ToInt32(stream.Length);
    Byte[] rtf = new Byte[size];
    stream.Read(rtf, 0, size);

    conn = new SqlConnection("Database=Northwind;Integrated Security=true;");
    conn.Open();
    cmd = new SqlCommand("UPDATE Employees SET Photo=@Photo WHERE EmployeeID=1", conn);

    SqlParameter paramRTF =
     new SqlParameter("@Photo",
     SqlDbType.Image,
     rtf.Length,
     ParameterDirection.Input,
     false,
     0,0,null,
     DataRowVersion.Current,
     rtf);
    cmd.Parameters.Add(paramRTF);
   
    int rowsUpdated = Convert.ToInt32(cmd.ExecuteNonQuery());
    
    MessageBox.Show(String.Format("{0} rows updated", rowsUpdated));
   }
   catch(Exception ex)
   {
    MessageBox.Show(ex.Message);
   }
   finally
   {
    if ( stream != null ) stream.Close();
    if (cmd != null ) cmd.Parameters.Clear();
    if (conn != null) conn.Close();
   }
  }

读取：

private void btnLoad_Click(object sender, System.EventArgs e)
  {
   richTextBox1.Clear();

   SqlConnection cn     = null;
   SqlCommand cmd       = null;
   SqlDataReader reader = null;
   try
   {
    cn = new SqlConnection("Database=Northwind;Integrated Security=true;");
    cn.Open();
    cmd = new SqlCommand("SELECT Photo FROM Employees WHERE EmployeeID=1", cn);
    reader = cmd.ExecuteReader();
    reader.Read();
    if (reader.HasRows)
    {
     if (!reader.IsDBNull(0))
     {
      Byte[] rtf = new Byte[Convert.ToInt32((reader.GetBytes(0, 0, null, 0, Int32.MaxValue)))];
      long bytesReceived = reader.GetBytes(0, 0, rtf, 0, rtf.Length);
 
      ASCIIEncoding encoding = new ASCIIEncoding();
      richTextBox1.Rtf = encoding.GetString(rtf, 0, Convert.ToInt32(bytesReceived));
     }
    }
   }
   catch(Exception ex)
   {
    MessageBox.Show(ex.Message);
   }
   finally
   {
    if (reader != null ) reader.Close();
    if (cn != null ) cn.Close();
   }

  }