Word Editor in Windows Forms

using GemBox.Document;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Drawing;
using System.IO;
using System.Windows.Forms;

namespace WindowsFormsRichTextEditor
{
    public partial class MainForm : Form
    {
        public MainForm()
        {
            InitializeComponent();

            // If using the Professional version, put your serial key below.
            ComponentInfo.SetLicense("FREE-LIMITED-KEY");
        }

        private void menuItemOpen_Click(object sender, EventArgs e)
        {
            var dialog = new OpenFileDialog()
            {
                AddExtension = true,
                Filter =
                    "All Documents (*.docx;*.docm;*.doc;*.dotx;*.dotm;*.dot;*.htm;*.html;*.rtf;*.xml;*.txt)|*.docx;*.docm;*.dotx;*.dotm;*.doc;*.dot;*.htm;*.html;*.rtf;*.xml;*.txt|" +
                    "Word Documents (*.docx)|*.docx|" +
                    "Word Macro-Enabled Documents (*.docm)|*.docm|" +
                    "Word 97-2003 Documents (*.doc)|*.doc|" +
                    "Word Templates (*.dotx)|*.dotx|" +
                    "Word Macro-Enabled Templates (*.dotm)|*.dotm|" +
                    "Word 97-2003 Templates (*.dot)|*.dot|" +
                    "Web Pages (*.htm;*.html)|*.htm;*.html|" +
                    "Rich Text Format (*.rtf)|*.rtf|" +
                    "Flat OPC (*.xml)|*.xml|" +
                    "Plain Text (*.txt)|*.txt"
            };

            if (dialog.ShowDialog() == System.Windows.Forms.DialogResult.OK)
                using (var stream = new MemoryStream())
                {
                    // Convert input file to RTF stream.
                    DocumentModel.Load(dialog.FileName).Save(stream, SaveOptions.RtfDefault);

                    stream.Position = 0;

                    // Load RTF stream into RichTextBox.
                    this.richTextBox.LoadFile(stream, RichTextBoxStreamType.RichText);
                }
        }

        private void btnSave_Click(object sender, EventArgs e)
        {
            var dialog = new SaveFileDialog()
            {
                AddExtension = true,
                Filter =
                    "Word Document (*.docx)|*.docx|" +
                    "Word Macro-Enabled Document (*.docm)|*.docm|" +
                    "Word Template (*.dotx)|*.dotx|" +
                    "Word Macro-Enabled Template (*.dotm)|*.dotm|" +
                    "PDF (*.pdf)|*.pdf|" +
                    "XPS Document (*.xps)|*.xps|" +
                    "Web Page (*.htm;*.html)|*.htm;*.html|" +
                    "Single File Web Page (*.mht;*.mhtml)|*.mht;*.mhtml|" +
                    "Rich Text Format (*.rtf)|*.rtf|" +
                    "Flat OPC (*.xml)|*.xml|" +
                    "Plain Text (*.txt)|*.txt|" +
                    "Image (*.png;*.jpg;*.jpeg;*.gif;*.bmp;*.tif;*.tiff;*.wdp,*.svg)|*.png;*.jpg;*.jpeg;*.gif;*.bmp;*.tif;*.tiff;*.wdp;*.svg"
            };

            if (dialog.ShowDialog(this) == System.Windows.Forms.DialogResult.OK)
                using (var stream = new MemoryStream())
                {
                    // Save RichTextBox content to RTF stream.
                    this.richTextBox.SaveFile(stream, RichTextBoxStreamType.RichText);

                    stream.Position = 0;

                    // Convert RTF stream to output format.
                    DocumentModel.Load(stream, LoadOptions.RtfDefault).Save(dialog.FileName);
                    Process.Start(dialog.FileName);
                }
        }

        private void DoGemBoxCopy()
        {
            using (var stream = new MemoryStream())
            {
                // Save RichTextBox selection to RTF stream.
                var writer = new StreamWriter(stream);
                writer.Write(this.richTextBox.SelectedRtf);
                writer.Flush();

                stream.Position = 0;

                // Save RTF stream to clipboard.
                DocumentModel.Load(stream, LoadOptions.RtfDefault).Content.SaveToClipboard();
            }
        }

        private void DoGemBoxPaste(bool prepend)
        {
            using (var stream = new MemoryStream())
            {
                // Save RichTextBox content to RTF stream.
                var writer = new StreamWriter(stream);
                writer.Write(this.richTextBox.SelectedRtf);
                writer.Flush();

                stream.Position = 0;

                // Load document from RTF stream and prepend or append clipboard content to it.
                var document = DocumentModel.Load(stream, LoadOptions.RtfDefault);
                var content = document.Content;
                (prepend ? content.Start : content.End).LoadFromClipboard();

                stream.Position = 0;

                // Save document to RTF stream.
                document.Save(stream, SaveOptions.RtfDefault);

                stream.Position = 0;

                // Load RTF stream into RichTextBox.
                var reader = new StreamReader(stream);
                this.richTextBox.SelectedRtf = reader.ReadToEnd();
            }
        }
    }
}