Linq provider for VSTS/TFS workitem queries

Prerequisites

This provider uses the VSTS Rest API to query the workitem repository. The provider uses the standard nuget client package

How it queries works

The provider works like extensions to the WorkItemTrackingHttpClient class:

Queries on the WorkItem class

The provider support queries on the standard WorkItem class. Use the Field extention method to target specific workitem fields:

var assignedToMe =	from workitem in Client.All()
                    where workitem.Field<string>("System.AssignedTo") == QueryConstant.Me
                    select workitem;

Queries on Generic workitem

The provider contains a specific GenericWorkItem class. This class has the following purposes:

• base class for types workitems
• typed fields
• to hide the complexity of the update api

var projectWiQuery = from bug in Client.SetOf<GenericWorkItem>()
                where bug.CreatedBy == bug.ChangedBy
                select bug;

Queries on Typed workitems

You can inherits from the Generic WorkItem class and create typed version of workitems. When used, the provider automaticaly add a filter on the workitem type

Bug definition:

[WorkItemType("Bug")]
public class Bug : GenericWorkItem
{
    [Field("Microsoft.VSTS.Common.Priority")]
    public virtual int? Priority
    {
        get => GetStructField<int>("Microsoft.VSTS.Common.Priority");
        set => SetStructField("Microsoft.VSTS.Common.Priority", value);
    }
   
}

Query on bugs:

var projectWiQuery = from bug in Client.SetOf<Bug>()
    where bug.CreatedBy == bug.ChangedBy && bug.Priority == 2
    select bug;

Queries on Process Template

You can register a set of typed workitems and let the provider instanciate the right version:

public class ScrumTemplate : ProcessTemplate
    {
        public ScrumTemplate()
        {
            AddWorkItemType<Epic>();
            AddWorkItemType<Feature>();
            AddWorkItemType<ProductBacklogItem>();
            AddWorkItemType<Bug>();
            AddWorkItemType<Task>();
           // ...
        }
    }

var q = from workitem in Client.FromTemplate<ScrumTemplate>()                
                select workitem;

Syn or Async queries

As any linq provider, sync queries are supported. You can also use a specific extension method to retrieve the data as an async query:

var projectWiQuery = from bug in Client.SetOf<Bug>(Project)
    where bug.IsUnderIteration(iteration)
    select bug;

            
var result = await projectWiQuery.ToListAsync();

Create and save typed workitems

Typed workitems can be created and saved by using the New<> and Save<> methods:

 var bug = Project.New<Bug>();

bug.Title = "New bug created";

await Client.Save(bug);

bug.Title = "Title Changed";
bug.Priority = 2;

await Client.Save(bug);