i am getting Getting Object reference not set to an instance of an object error 
my code and the image are attached below
   public class Backlogitem
        {
            public string Name { get; set; }
            public int ID { get; set; }
            public string State { get; set; }
           // public DateTime? due { get; set; }
            public int priorty { get; set; }
            public int Size { get; set; }
          //  public int effort { get; set; }
            public int StoryPoints { get; set; }
            public string DoneStatus { get; set; }
            public string StoryOwner { get; set; }
            public string Assignedto { get; set; }
            public string StoryAuthor { get; set; }
            public string IterationPath { get; set; }
        }
workitemlist image 
 rest of the code is pasted here
rest of the code is pasted here 
https://github.com/akhiljain1611/TFS/blob/master/README.md


 
    