Sharepoint 2010: create a lookup column that refers to files of a specific content type in a document library

Question

I need to create a lookup column in sharepoint 2010 that refers to files of a specified content type. Files are all resident in a document library organized as folder.

More precisely:

• I've the DocLib1 with files with different content type (e.g. ContentType1, ContentType2)
• I need to create a lookup column (in a different list, but I think this should not matter) that refers to DocLib1 and refers only files of ContentType1 (and not files of ContentType2).

I know how to create lookup columns in SP Web interface or SharePoint Designer. If necessary, I can also create the column in Visual Studio using C# or elements.xml.

Answer 1

I tried to create a lookup column that references documents by Name column before, but it doesn't work like you'd expect. While the value stored in the lookup column is valid, it doesn't show up right in list view or in item display from. Currently I use Lookup Extra field type for documents lookup. It also supports filter documents by content type.