Novacode.DocX.AddCustomProperty C# (CSharp) Method

        public void AddCustomProperty(CustomProperty cp)
        {
            // If this document does not contain a customFilePropertyPart create one.
            if (!package.PartExists(new Uri("/docProps/custom.xml", UriKind.Relative)))
                HelperFunctions.CreateCustomPropertiesPart(this);

            XDocument customPropDoc;
            PackagePart customPropPart = package.GetPart(new Uri("/docProps/custom.xml", UriKind.Relative));
            using (TextReader tr = new StreamReader(customPropPart.GetStream(FileMode.Open, FileAccess.Read)))
                customPropDoc = XDocument.Load(tr, LoadOptions.PreserveWhitespace);

            // Each custom property has a PID, get the highest PID in this document.
            IEnumerable<int> pids =
            (
                from d in customPropDoc.Descendants()
                where d.Name.LocalName == "property"
                select int.Parse(d.Attribute(XName.Get("pid")).Value)
            );

            int pid = 1;
            if (pids.Count() > 0)
                pid = pids.Max();

            // Check if a custom property already exists with this name
            // 2013-05-25: IgnoreCase while searching for custom property as it would produce a currupted docx.
            var customProperty =
            (
                from d in customPropDoc.Descendants()
                where (d.Name.LocalName == "property") && (d.Attribute(XName.Get("name")).Value.Equals(cp.Name, StringComparison.InvariantCultureIgnoreCase))
                select d
            ).SingleOrDefault();

            // If a custom property with this name already exists remove it.
            if (customProperty != null)
                customProperty.Remove();

            XElement propertiesElement = customPropDoc.Element(XName.Get("Properties", customPropertiesSchema.NamespaceName));
            propertiesElement.Add
            (
                new XElement
                (
                    XName.Get("property", customPropertiesSchema.NamespaceName),
                    new XAttribute("fmtid", "{D5CDD505-2E9C-101B-9397-08002B2CF9AE}"),
                    new XAttribute("pid", pid + 1),
                    new XAttribute("name", cp.Name),
                        new XElement(customVTypesSchema + cp.Type, cp.Value ?? "")
                )
            );

            // Save the custom properties
            using (TextWriter tw = new StreamWriter(new PackagePartStream(customPropPart.GetStream(FileMode.Create, FileAccess.Write))))
                customPropDoc.Save(tw, SaveOptions.None);

            // Refresh all fields in this document which display this custom property.
            UpdateCustomPropertyValue(this, cp.Name, (cp.Value ?? "").ToString());
        }

        public override void MergeField(DocX doc)
        {
            base.MergeField(doc);

            doc.AddCustomProperty(new Novacode.CustomProperty("ProductPart.LabelsPerRoll", this.LabelsPerRoll??0));
            doc.AddCustomProperty(new Novacode.CustomProperty("ProductPart.SoulDiameter", this.SoulDiameter ?? 0));
            doc.AddCustomProperty(new Novacode.CustomProperty("ProductPart.MaxDiameter", this.MaxDiameter ?? 0));
        }