docx的编码标准是什么?(编码并保存字符串到数据库)c#

我想保存在数据库(mssql)我的HTMLEDITOR的信息，但当我编码数据并保存它很好，但当我恢复它或打开它的数据，他们不打开什么。我想问题出在编码标准上。

      using (var output = new MemoryStream())
        {
            string docx = string.Empty;
            byte[] bytesDocx = null;
            this.ASPxHtmlEditorTemplate.Export(HtmlEditorExportFormat.Docx, output);//pass the data of the editor and assign to stream
            output.Flush();
            output.Position = 0;
            using (var reader = new StreamReader(output))
            {
                docx = reader.ReadToEnd();// assign the stream to a STRING
                bytesDocx = Encoding.UTF-8.GetBytes(docx);//encode the STRING to UTF-8
                using (var uow = new UnitOfWork())
                {
                    //here some instructions to save the "bytes" to TEXT in a MSSQL DB
                    uow.CommitChanges();
                }
            }

XmlDocument xmldoc = new XmlDocument();
xmldoc.Load(docxStream);
string text = xmldoc.DocumentElement.InnerText;