Problem

WordApplication does not currently have support for inserting fields other than MergeFields and Hyperlinks. You want to insert a different kind of field, such as the current page number.

Solution

WordWriter has a MergeField class and a Hyperlink class which allow you to programmatically insert those fields. However, those are currently the only two fields which are included in the WordWriter API. In order to insert a field such as a page number into a newly generated document in WordApplication, you must first create a document with Microsoft Word and copy the field from there.

Inserting Footers with Fields

If you wish to create a footer which includes a field such as the page number, you must first create a document in Microsoft Word. Add all the text, fields, and formatting that you wish to appear in the final document to this file. For the purposes of this article, this file will be called ‘footer.doc’.*

In order to use your newly created footer, you must open the document in your WordApplication and copy the footer into the document you are generating programmatically:

//Create the document you want to insert a footer into
Document doc = wa.Create();

//Or open an existing file, instead of creating one
//Document doc = wa.Open("myFile.doc");

//Open the document with the footer you want to copy
Document footerDoc = wa.Open(Page.MapPath("footer.doc"));

//Get the footers for both documents
Element footerSource = footerDoc.Sections[0].get_Footer(Section.HeaderFooterType.All);
Element footerDestination = doc.Sections[0].get_Footer(Section.HeaderFooterType.All);

//Insert the footer into the destination document
footerDestination.InsertAfter(footerSource);
In this way, you can copy the footer into a newly generated document or one that was opened from a different file. For more information about retrieving footers or headers and inserting them as Elements, see the documentation for the Section and the Element classes.

Inserting Headers with Fields

Copying the header is very similar to copying the footer, except that you would insert the header Element instead of the footer. So if you have a document called ‘header.doc’ that you wish to copy the header from, you can say:

//Create the document you want to insert a header into
Document doc = wa.Create();

//Or open an existing file, instead of creating one
//Document doc = wa.Open("myFile.doc");

//Open the document with the header you want to copy
Document headerDoc = wa.Open(Page.MapPath("header.doc"));

//Get the headers for both documents
Element headerSource = footerDoc.Sections[0].get_Header(Section.HeaderFooterType.All);
Element headerDest = doc.Sections[0].get_Header(Section.HeaderFooterType.All);

//Insert the header into the document
headerDest.InsertAfter(headerSource);

Inserting Fields into the Body of a Document

If you instead want to insert a field into the body of the document along with programmatically generated content, you can retrieve only the Field Element from a pregenerated file. For example, if you want to insert a ‘Date’ field into the body of a document, you must first create a new file in Microsoft Word. Add a Date field to the body of this new document by going to Insert->Field and choosing Date. Save the document. For the purposes of this article, the file will be called ‘datefield.doc’.

In your WordApplication, when you want to insert the field, you will open the datefield.doc document, retrieve the field, and insert it into your own document:

//Open the document with the date field in it
Document fieldDoc = wa.Open(Page.MapPath("datefield.doc"));

//Get the date field from the body of the document. We use an index of 0
//because it is the first (and only) field element in the document.
Element dateField = fieldDoc.get_Elements(Element.Type.Field)[0];

//Insert the date field into the body of another document (called 'doc').
doc.InsertAfter(dateField);

In this way, you can programmatically add Microsoft Word fields to a newly generated document. For more information about how to specify what type of Element you want to retrieve from the document, see the documentation for the Elements property of the Element class and refer to the different types of Elements that you can ask for.