Is there any point to specifying any fields other than "Id" when using WorkItemTrackingHttpClient.QueryByWiqlAsync()?

Question

I've been looking at several Microsoft code samples for using WorkItemTrackingHttpClient.QueryByWiqlAsync(), and they all specify a number of fields in addition to the "Id" field.

For example, from this code sample:

Wiql wiql = new Wiql()
{
    Query = "Select [State], [Title] " +
            "From WorkItems " +
            "Where [Work Item Type] = 'Bug' " +
            "And [System.TeamProject] = '" + project + "' " +
            "And [System.State] <> 'Closed' " +
            "Order By [State] Asc, [Changed Date] Desc"
};

Then the code goes on to use this query:

WorkItemQueryResult workItemQueryResult =
    workItemTrackingHttpClient.QueryByWiqlAsync(wiql).Result;

But then the following code extracts only the IDs from the query and uses them to get the actual work items, using workItemTrackingHttpClient.GetWorkItemsAsync():

List<int> list = new List<int>();
foreach (var item in workItemQueryResult.WorkItems)
{
    list.Add(item.Id);
}
int[] arr = list.ToArray();

//build a list of the fields we want to see
string[] fields = new string[3];
fields[0] = "System.Id";
fields[1] = "System.Title";
fields[2] = "System.State";

//get work items for the id's found in query
var workItems = workItemTrackingHttpClient.GetWorkItemsAsync(arr, fields, workItemQueryResult.AsOf).Result;

I discovered that you only need to "Select [Id] FROM workitems ...", because only the ID is actually used. In fact, I can find no direct way of accessing the other fields in the WorkItemQueryResult results returned from QueryByWiqlAsync().

So what am I missing? Why do all the Microsoft code samples specify a variety of columns for the query, but then just ignore them all? Is it just a mistake, or is there some fundamental reason that I'm unaware of?

Answer 1

My guess is that they copied the WIQL expression from an existing query.

As the REST API only returns the IDs and the .NET client libraries for Azure DevOps are just a thin wrapper around the REST API, the client libraries can't surface data that isn't returned by the REST API.

See the example response (shortened by me) from the docs

{
  "queryType": "flat",
  "asOf": "2014-12-29T20:49:34.617Z",
  "columns": [
    {
      "referenceName": "System.Id",
      "name": "ID",
      "url": "https://dev.azure.com/fabrikam/_apis/wit/fields/System.Id"
    },
    {
      "referenceName": "System.Title",
      "name": "Title",
      "url": "https://dev.azure.com/fabrikam/_apis/wit/fields/System.Title"
    },
    {
      "referenceName": "System.State",
      "name": "State",
      "url": "https://dev.azure.com/fabrikam/_apis/wit/fields/System.State"
    }
  ],
  "sortColumns": [
    {
      "field": {
        "referenceName": "Microsoft.VSTS.Common.Priority",
        "name": "Priority",
        "url": "https://dev.azure.com/fabrikam/_apis/wit/fields/Microsoft.VSTS.Common.Priority"
      },
      "descending": false
    },
    {
      "field": {
        "referenceName": "System.CreatedDate",
        "name": "Created Date",
        "url": "https://dev.azure.com/fabrikam/_apis/wit/fields/System.CreatedDate"
      },
      "descending": true
    }
  ],
  "workItems": [
    {
      "id": 300,
      "url": "https://dev.azure.com/fabrikam/_apis/wit/workItems/300"
    },
    {
      "id": 299,
      "url": "https://dev.azure.com/fabrikam/_apis/wit/workItems/299"
    }
  ]
}