Novacode.DocX.UpdateCustomPropertyValue C# (CSharp) Method

        internal static void UpdateCustomPropertyValue(DocX document, string customPropertyName, string customPropertyValue)
        {
            // A list of documents, which will contain, The Main Document and if they exist: header1, header2, header3, footer1, footer2, footer3.
            List<XElement> documents = new List<XElement> { document.mainDoc.Root };

            // Check if each header exists and add if if so.
            #region Headers
            Headers headers = document.Headers;
            if (headers.first != null)
                documents.Add(headers.first.Xml);
            if (headers.odd != null)
                documents.Add(headers.odd.Xml);
            if (headers.even != null)
                documents.Add(headers.even.Xml);
            #endregion

            // Check if each footer exists and add if if so.
            #region Footers
            Footers footers = document.Footers;
            if (footers.first != null)
                documents.Add(footers.first.Xml);
            if (footers.odd != null)
                documents.Add(footers.odd.Xml);
            if (footers.even != null)
                documents.Add(footers.even.Xml);
            #endregion

            var matchCustomPropertyName = customPropertyName;
            if (customPropertyName.Contains(" ")) matchCustomPropertyName = "\"" + customPropertyName + "\"";
            string match_value = string.Format(@"DOCPROPERTY  {0}  \* MERGEFORMAT", matchCustomPropertyName).Replace(" ", string.Empty);

            // Process each document in the list.
            foreach (XElement doc in documents)
            {
                #region Word 2010+
                foreach (XElement e in doc.Descendants(XName.Get("instrText", w.NamespaceName)))
                {

                    string attr_value = e.Value.Replace(" ", string.Empty).Trim();

                    if (attr_value.Equals(match_value, StringComparison.CurrentCultureIgnoreCase))
                    {
                        XNode node = e.Parent.NextNode;
                        bool found = false;
                        while (true)
                        {
                            if (node.NodeType == XmlNodeType.Element)
                            {
                                var ele = node as XElement;
                                var match = ele.Descendants(XName.Get("t", w.NamespaceName));
                                if (match.Any())
                                {
                                    if (!found)
                                    {
                                        match.First().Value = customPropertyValue;
                                        found = true;
                                    }
                                    else
                                    {
                                        ele.RemoveNodes();
                                    }
                                }
                                else
                                {
                                    match = ele.Descendants(XName.Get("fldChar", w.NamespaceName));
                                    if (match.Any())
                                    {
                                        var endMatch = match.First().Attribute(XName.Get("fldCharType", w.NamespaceName));
                                        if (endMatch != null && endMatch.Value == "end")
                                        {
                                            break;
                                        }
                                    }
                                }
                            }
                            node = node.NextNode;
                        }
                    }
                }
                #endregion

                #region < Word 2010
                foreach (XElement e in doc.Descendants(XName.Get("fldSimple", w.NamespaceName)))
                {
                    string attr_value = e.Attribute(XName.Get("instr", w.NamespaceName)).Value.Replace(" ", string.Empty).Trim();

                    if (attr_value.Equals(match_value, StringComparison.CurrentCultureIgnoreCase))
                    {
                        XElement firstRun = e.Element(w + "r");
                        XElement firstText = firstRun.Element(w + "t");
                        XElement rPr = firstText.Element(w + "rPr");

                        // Delete everything and insert updated text value
                        e.RemoveNodes();

                        XElement t = new XElement(w + "t", rPr, customPropertyValue);
                        Novacode.Text.PreserveSpace(t);
                        e.Add(new XElement(firstRun.Name, firstRun.Attributes(), firstRun.Element(XName.Get("rPr", w.NamespaceName)), t));
                    }
                }
                #endregion
            }
        }