Question

I’m using Sharepoint 2010’s web services interface to try to get the columns for a given list. I’ve got not problem with getting all of the columns using a GetList() call, but the issue is that I need to only get the columns that the user can see in the List Settings view of the Sharepoint UI.

The code that I’m currently using is as follows:

rootNode = serviceReference.GetList(List_id.ToString());
Element element = XElement.Parse(rootNode.OuterXml);
var fields = from e in element.Descendants()
             where e.Name.LocalName == "Field" && e.Attribute("ID") != null &&
             !(e.Attribute("Name").Value.StartsWith("_") && e.Attribute("SourceID").Value == "http://schemas.microsoft.com/sharepoint/v3")            
             select e;

Where serviceReference is an instance of the Sharepoint Lists Service and List_id is the GUID representing the list internally to Sharepoint.

This does filter out some of the columns that I don’t want, but it doesn’t get rid of everything.

Does anybody know what attributes I’m looking for to narrow it down just to the ones that the user can select to be added to a view? Or am I going about this entirely the wrong way?

Many thanks for any help.

Answer 1

The answer to this was that I was indeed looking in the wrong place for the information I needed. As user823959 pointed out, I needed to get the content type definition and use the fields in there rather than the list itself.

To do this was a two stage process, firstly we need to get the list of content types using the Lists.GetListContentTypes method (although this takes a content type id parameter, it doesn’t actually seem to matter what we put here)

    XmlNode rootNode = serviceReference.GetListContentTypes(List_id.ToString(), "0×01");

The CAML returned contains the definitions for each of the content types that are available in the list – with the first content type returned being the default one (in my case, the one I was after)

    String contentType = rootNode.ChildNodes[0].Attributes["ID"].Value;

Once we’ve got the content type that we’re after we can make a call to GetListContentType with the appropriate list content type id to get the full definition of the content type:

    XmlNode contentTypeNode = serviceReference.GetListContentType(List_id.ToString(), contentType);

The CAML returned from this call will contain a list of field elements that correctly show the fields that are available in the SharePoint UI’s view configuration. They can be selected in a LINQ query like this:

    XElement contentTypesElement = XElement.Parse(contentTypeNode.OuterXml);

    var fields = from e in contentTypesElement.Descendants()
                 where e.Name.LocalName == "Field"
                 select e;

At this point, we’ve got a list of Field XML elements that contain information about display names, static names, content types and a whole lot more. See Microsoft’s documentation on the Lists.GetListContentType page for more information on the range of information returned about each field.

Many Thanks to user823959 for pointing me in the right direction.