Rtf&Html Converter

public static class DevExpressConverter
{
    public static string ConvertRtfToHtml(string rtf)
    {
        var ms = new MemoryStream();
        var writer = new StreamWriter(ms);
        writer.Write(rtf);
        writer.Flush();
        ms.Position = 0;
        var output = "";
        HtmlEditorExtension.Import(HtmlEditorImportFormat.Rtf, ms, (s, enumerable) => output = s);

        return output;
    }

    public static string ConvertHtmlToRtf(string html)
    {
        var ms = new MemoryStream();
        var editor = new ASPxHtmlEditor { Html = html };

        editor.Export(HtmlEditorExportFormat.Rtf, ms);
                
        ms.Position = 0;
        var reader = new StreamReader(ms);

        return reader.ReadToEnd();
    }
}

public static class WindowsFormsConverter
{
    public static string ConvertHtmlToRtf(string html)
    {
        var webBrowser = new WebBrowser { DocumentText = html };
        while (webBrowser.DocumentText != html)
            Application.DoEvents();

        if (webBrowser.Document == null)
            return null;

        webBrowser.Document.ExecCommand("SelectAll", false, null);
        webBrowser.Document.ExecCommand("Copy", false, null);

        var richTextbox = new RichTextBox();
        richTextbox.Paste();

        return richTextbox.Rtf;
    }
}

public static class SautinSoftConverter
{
    public static string ConvertHtmlToRtf(string html, string licenseSerial, string baseUrl = null)
    {
        var h = new HtmlToRtf { Serial = licenseSerial };

        if(baseUrl != null)
            h.BaseURL = baseUrl;

        return h.ConvertString(html);
    }
}

public static class OpenXmlConverter
{
    public static byte[] ConvertHtmlToOpenXml(string html)
    {
        using (var generatedDocument = new MemoryStream())
        {
            using (var package = WordprocessingDocument.Create(generatedDocument, WordprocessingDocumentType.Document))
            {
                var mainPart = package.MainDocumentPart;
                if (mainPart == null)
                {
                    mainPart = package.AddMainDocumentPart();
                    new Document(new Body()).Save(mainPart);
                }

                var converter = new HtmlConverter(mainPart);
                converter.ParseHtml(html);

                mainPart.Document.Save();
            }

            return generatedDocument.ToArray();
        }
    }
}