A while ago I stumbled upon a serious design limitation regarding Content Types and centralized document templates. What then followed was a series of testing, phone calls with Microsoft, finding alternative solutions and deep dive into Office Open XML.
Request from the customer
“We want to use MOSS 2007 to create a collaboration site per project for our 400+ projects. These collaboration sites all use the same Content Types and document templates. We want to centrally manage those document templates so that we don’t need to make the same change 400+ times.”
Due to sizing we architected a solution with a dozen of Site Collections that would each hold a collection of project sites. We ‘Feature’-ized our Content Types and Site Columns so that they could quickly be activated on all Site Collections and used by the child sites. Document templates would be stored in a central document library and we would link to them in the Content Types on the project sites.
Linking to document templates really doesn’t play well with the Document Information Panel (DIP). I have blogged about this here:
Centralizing Document Templates in a library- Document Information Panel shows incorrect properties
We proposed a solution where the document templates in the central library would be pushed to the Content Type resource folder on site level. The code to perform the push would have to connect to the Site Collections, copy the template to the resource folder (http://sitecollectionurl/_cts/contenttypename) and link template and Content Type together.
When a Site Content Type is associated with a List it will be a List Content Type inheriting from the Site Content Type and the document template will be copied to the List Content Type resource folder (http://sitecollectionurl/listurl/Forms/contenttypename).
Did I tell you that the column values (metadata) have different values based on the project site ? So when a project site is created we automatically update the List Content Type Column default value with the values for that specific project site. Unfortunately this is not supported when working with Office 2007 file formats because they only react on changes to the Site Column.
Consider the following scenario:
1) Set up a document library with a Content Type that has a text column with a default value
2) Upload a new .doc or .docx as Content Type template
TEST 1) Create a new document:
.DOC: the DIP will contain the text column with the default value
.DOCX: the DIP will contain the text column with the default value
3) In SharePoint, modify the default value of the text column
TEST 2) Create a new document:
.DOC: the DIP will contain the text column with the updated default value
.DOCX: the DIP will contain the text column with the original default value
Microsoft confirmed that this is by design.
When designing our document templates with Content Controls mapped to our SharePoint fields we didn’t know that internally in the DOCX file it uses a GUID for mapping the Content Control with the SharePoint Metadata XML. For fields (Site Columns) created in the UI or through API this is the SPWeb.ID of where they were created. For fields created declaratively through Features this is the SPList.ID of where their Content Type is associated to.
So some things to notice
- Creating a single document template with Content Controls mapped to your declaratively added Fields cannot be used in two different Document Libraries because the Content Controls lose the connection with Field (because the ID of the List is different and not updated in the Content Control)
- The solution here is to create your fields in the UI or through the API (this could be in a Feature Activating event)
- Copying a document template across Site Collections means different Web ID’s so it also affects fields created in the UI or the API
In the end we wrote some wrapper classes for Office 2007 file formats using System.IO.Packaging that would manipulate our document templates once they were copied over to a different Site Collection. We also rewrote our Features to create our Fields through the API (SPWeb.Fields.AddFieldAsXml()).
- Remove the SharePoint Metadata XML so that association of the Content Type to a List it would be regenerated automagically
- Loop through every Content Control and find to which Field they were mapped using information in it’s XPath. Then we would update the GUID’s in the Content Control to match the SPWeb.ID
Next time I’ll definitely take these design limitations into account. Lessons learned I’d say !