C#
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Net.Mail;
using DevExpress.XtraRichEdit;
using DevExpress.Utils;
using DevExpress.Office.Services;
using System.Net.Mime;
using System.IO;
using DevExpress.XtraRichEdit.Export;
using DevExpress.XtraRichEdit.Export.Html;
using System.Net;
using DevExpress.Office.Utils;

namespace RichEditSendMail {
    public partial class Form1 : DevExpress.XtraEditors.XtraForm
    {
        public Form1() {
            InitializeComponent();

            richEdit.LoadDocument("Hello.docx");
        }

        private void btnSend_Click(object sender, EventArgs e) {
            if ((edtTo.Text.Trim() == "") || (edtSubject.Text.Trim() == "") || (edtSmtp.Text.Trim() == ""))
            {
                MessageBox.Show("Fill in required fields");
                return;
            }

            try
            {
                MailMessage mailMessage = new MailMessage("XtraRichEdit@devexpress.com", edtTo.Text);
                mailMessage.Subject = edtSubject.Text;

                RichEditMailMessageExporter exporter = new RichEditMailMessageExporter(richEdit, mailMessage);
                exporter.Export();

                SmtpClient mailSender = new SmtpClient(edtSmtp.Text);
                //specify your login/password to log on to the SMTP server, if required
                //mailSender.Credentials = new NetworkCredential("login", "password");
                mailSender.Send(mailMessage);
                MessageBox.Show("Message sent", "RichEditSendMail", MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
            catch (Exception exc) {
                MessageBox.Show(exc.Message);
            
            }
        }

        public class RichEditMailMessageExporter : IUriProvider {
            readonly RichEditControl control;
            readonly MailMessage message;
            List<AttachementInfo> attachments;
            int imageId;

            public RichEditMailMessageExporter(RichEditControl control, MailMessage message) {
                Guard.ArgumentNotNull(control, "control");
                Guard.ArgumentNotNull(message, "message");

                this.control = control;
                this.message = message;
                
            }

            public virtual void Export() {
                this.attachments = new List<AttachementInfo>();

                AlternateView htmlView = CreateHtmlView();
                message.AlternateViews.Add(htmlView);
                message.IsBodyHtml = true;
            }

            protected internal virtual AlternateView CreateHtmlView() {
                control.BeforeExport += OnBeforeExport;
                string htmlBody = control.Document.GetHtmlText(control.Document.Range, this);
                AlternateView view = AlternateView.CreateAlternateViewFromString(htmlBody, Encoding.UTF8, MediaTypeNames.Text.Html);
                control.BeforeExport -= OnBeforeExport;

                int count = attachments.Count;
                for (int i = 0; i < count; i++) {
                    AttachementInfo info = attachments[i]; 
                    LinkedResource resource = new LinkedResource(info.Stream, info.MimeType);
                    resource.ContentId = info.ContentId;
                    view.LinkedResources.Add(resource);
                }
                return view;
            }

            void OnBeforeExport(object sender, BeforeExportEventArgs e) {
                HtmlDocumentExporterOptions options = e.Options as HtmlDocumentExporterOptions;
                if (options != null) {
                    options.Encoding = Encoding.UTF8;
                }
            }


            #region IUriProvider Members
            
            public string CreateCssUri(string rootUri, string styleText, string relativeUri) {
                return String.Empty;
            }
            public string CreateImageUri(string rootUri, OfficeImage image, string relativeUri) {
                string imageName = String.Format("image{0}", imageId);
                imageId++;

                OfficeImageFormat imageFormat = GetActualImageFormat(image.RawFormat);
                Stream stream = new MemoryStream(image.GetImageBytes(imageFormat));
                string mediaContentType = OfficeImage.GetContentType(imageFormat);
                AttachementInfo info = new AttachementInfo(stream, mediaContentType, imageName);
                attachments.Add(info);

                return "cid:" + imageName;
            }

            OfficeImageFormat GetActualImageFormat(OfficeImageFormat _officeImageFormat) {
                if (_officeImageFormat == OfficeImageFormat.Exif ||
                    _officeImageFormat == OfficeImageFormat.MemoryBmp)
                    return OfficeImageFormat.Png;
                else
                    return _officeImageFormat;
            }
            #endregion
        }

        public class AttachementInfo {
            Stream stream;
            string mimeType;
            string contentId;

            public AttachementInfo(Stream stream, string mimeType, string contentId) {
                this.stream = stream;
                this.mimeType = mimeType;
                this.contentId = contentId;
            }

            public Stream Stream { get { return stream; } }
            public string MimeType { get { return mimeType; } }
            public string ContentId { get { return contentId; } }
        }
    }
}

Visual Basic
Imports System
Imports System.Collections.Generic
Imports System.ComponentModel
Imports System.Drawing
Imports System.Text
Imports System.Windows.Forms
Imports System.Net.Mail
Imports DevExpress.XtraRichEdit
Imports DevExpress.Utils
Imports DevExpress.Office.Services
Imports System.Net.Mime
Imports System.IO
Imports DevExpress.XtraRichEdit.Export
Imports DevExpress.Office.Utils

Namespace RichEditSendMail

    Public Partial Class Form1
        Inherits DevExpress.XtraEditors.XtraForm

        Public Sub New()
            InitializeComponent()
            richEdit.LoadDocument("Hello.docx")
        End Sub

        Private Sub btnSend_Click(ByVal sender As Object, ByVal e As EventArgs)
            If(Equals(edtTo.Text.Trim(), "")) OrElse (Equals(edtSubject.Text.Trim(), "")) OrElse (Equals(edtSmtp.Text.Trim(), "")) Then
                MessageBox.Show("Fill in required fields")
                Return
            End If

            Try
                Dim mailMessage As MailMessage = New MailMessage("XtraRichEdit@devexpress.com", edtTo.Text)
                mailMessage.Subject = edtSubject.Text
                Dim exporter As RichEditMailMessageExporter = New RichEditMailMessageExporter(richEdit, mailMessage)
                exporter.Export()
                Dim mailSender As SmtpClient = New SmtpClient(edtSmtp.Text)
                'specify your login/password to log on to the SMTP server, if required
                'mailSender.Credentials = new NetworkCredential("login", "password");
                mailSender.Send(mailMessage)
                MessageBox.Show("Message sent", "RichEditSendMail", MessageBoxButtons.OK, MessageBoxIcon.Information)
            Catch exc As Exception
                MessageBox.Show(exc.Message)
            End Try
        End Sub

        Public Class RichEditMailMessageExporter
            Implements IUriProvider

            Private ReadOnly control As RichEditControl

            Private ReadOnly message As MailMessage

            Private attachments As List(Of AttachementInfo)

            Private imageId As Integer

            Public Sub New(ByVal control As RichEditControl, ByVal message As MailMessage)
                Guard.ArgumentNotNull(control, "control")
                Guard.ArgumentNotNull(message, "message")
                Me.control = control
                Me.message = message
            End Sub

            Public Overridable Sub Export()
                attachments = New List(Of AttachementInfo)()
                Dim htmlView As AlternateView = CreateHtmlView()
                message.AlternateViews.Add(htmlView)
                message.IsBodyHtml = True
            End Sub

            Protected Friend Overridable Function CreateHtmlView() As AlternateView
                AddHandler control.BeforeExport, AddressOf OnBeforeExport
                Dim htmlBody As String = control.Document.GetHtmlText(control.Document.Range, Me)
                Dim view As AlternateView = AlternateView.CreateAlternateViewFromString(htmlBody, Encoding.UTF8, MediaTypeNames.Text.Html)
                RemoveHandler control.BeforeExport, AddressOf OnBeforeExport
                Dim count As Integer = attachments.Count
                For i As Integer = 0 To count - 1
                    Dim info As AttachementInfo = attachments(i)
                    Dim resource As LinkedResource = New LinkedResource(info.Stream, info.MimeType)
                    resource.ContentId = info.ContentId
                    view.LinkedResources.Add(resource)
                Next

                Return view
            End Function

            Private Sub OnBeforeExport(ByVal sender As Object, ByVal e As BeforeExportEventArgs)
                Dim options As HtmlDocumentExporterOptions = TryCast(e.Options, HtmlDocumentExporterOptions)
                If options IsNot Nothing Then
                    options.Encoding = Encoding.UTF8
                End If
            End Sub

#Region "IUriProvider Members"
            Public Function CreateCssUri(ByVal rootUri As String, ByVal styleText As String, ByVal relativeUri As String) As String Implements IUriProvider.CreateCssUri
                Return String.Empty
            End Function

            Public Function CreateImageUri(ByVal rootUri As String, ByVal image As OfficeImage, ByVal relativeUri As String) As String Implements IUriProvider.CreateImageUri
                Dim imageName As String = String.Format("image{0}", imageId)
                imageId += 1
                Dim imageFormat As OfficeImageFormat = GetActualImageFormat(image.RawFormat)
                Dim stream As Stream = New MemoryStream(image.GetImageBytes(imageFormat))
                Dim mediaContentType As String = OfficeImage.GetContentType(imageFormat)
                Dim info As AttachementInfo = New AttachementInfo(stream, mediaContentType, imageName)
                attachments.Add(info)
                Return "cid:" & imageName
            End Function

            Private Function GetActualImageFormat(ByVal _officeImageFormat As OfficeImageFormat) As OfficeImageFormat
                If _officeImageFormat = OfficeImageFormat.Exif OrElse _officeImageFormat = OfficeImageFormat.MemoryBmp Then
                    Return OfficeImageFormat.Png
                Else
                    Return _officeImageFormat
                End If
            End Function
#End Region
        End Class

        Public Class AttachementInfo

            Private streamField As Stream

            Private mimeTypeField As String

            Private contentIdField As String

            Public Sub New(ByVal stream As Stream, ByVal mimeType As String, ByVal contentId As String)
                streamField = stream
                mimeTypeField = mimeType
                contentIdField = contentId
            End Sub

            Public ReadOnly Property Stream As Stream
                Get
                    Return streamField
                End Get
            End Property

            Public ReadOnly Property MimeType As String
                Get
                    Return mimeTypeField
                End Get
            End Property

            Public ReadOnly Property ContentId As String
                Get
                    Return contentIdField
                End Get
            End Property
        End Class
    End Class
End Namespace