TFS API - How to obtain the parent of a work item

Question

My ultimate goal is to get the parent of one work item at a time recursively, until there are no more parents in the hierarchy. At the moment, there is nothing recursive yet, I am still at the point of optimizing the way I obtain the parent work item. I have thought of a way of doing this involving a query:

public WorkItem GetParentWorkItem(int id)
{
    StringBuilder queryString = new StringBuilder("SELECT [System.Id]" +    
                                                  " FROM WorkItemLinks " +
                                                  " WHERE [Source].[System.WorkItemType] = '" + TFS_TIMESHEET_WORK_ITEM_TYPE + "'"  +
                                                  " AND [Source].[System.TeamProject] = '" + TFS_TIMESHEET_PROJECT_KEY + "'" +
                                                  " AND [Source].[System.Id] = " + id 
                                                  );
    Query wiQuery = new Query(GetWorkItemStore, queryString.ToString());
    WorkItemLinkInfo[] wiTrees = wiQuery.RunLinkQuery();
    WorkItem wi = GetWorkItemStore.GetWorkItem(wiTrees[1].TargetId);

    return wi;
}

The problem with this method is that it gets all the linked work items, including predecessor, successor, child and parents. I knew that wiTrees[1] was the parent work item so I hard coded the index.

I found out a way to get the "parent" WorkItemTypeEnd object from the work item store:

WorkItemLinkTypeEnd linkTypEnd = GetWorkItemStore.WorkItemLinkTypes.LinkTypeEnds["Parent"];

Where do I go from here?

Answer 1

This works on TFS 2013:

var parent_link = work_item.WorkItemLinks.Cast<WorkItemLink> ().FirstOrDefault (x => x.LinkTypeEnd.Name == "Parent");

WorkItem parent_work_item = null;
if (parent_link != null)
    parent_work_item = work_item_store.GetWorkItem (parent_link.TargetId);

Answer 2

Found a solution, which returns the parent WorkItem if there is a parent, if not returns null.

public WorkItem GetParentWorkItem(int id)
    {
        StringBuilder queryString = new StringBuilder("SELECT [System.Id]" +    
                                                      " FROM WorkItemLinks " +
                                                      " WHERE [Source].[System.WorkItemType] = '" + TFS_TIMESHEET_WORK_ITEM_TYPE + "'" +
                                                      " AND [Source].[System.TeamProject] = '" + TFS_TIMESHEET_PROJECT_KEY + "'" +
                                                      " AND [Source].[System.Id] = " + id 
                                                      );
        Query wiQuery = new Query(GetWorkItemStore, queryString.ToString());
        WorkItemLinkInfo[] wiTrees = wiQuery.RunLinkQuery();

        int parentLinkId = GetWorkItemStore.WorkItemLinkTypes.LinkTypeEnds["Parent"].Id;

        foreach (WorkItemLinkInfo linkInfo in wiTrees)
        {
            // -2 is the LinkTypeId for parent
            if (linkInfo.LinkTypeId == parentLinkId)
            {
                workItem = GetWorkItemStore.GetWorkItem(linkInfo.TargetId);
                break;
            }
            else
            {
                workItem = null;
            }
        }
        return workItem;
    }