public void AddToTravelTest()
 {
     TravelDataServiceContext ctx = new TravelDataServiceContext
         (new Uri("http://localhost:28452/DataService/TravelDataService.svc"));
     Travel travel = new Travel()
     {
         PartitionKey = "Lanxing",
         RowKey = Guid.NewGuid(),
         Place = "Shanghai",
         Latitude = 31,
         Longitude = 121,
         Time = DateTime.Now
     };
     ctx.AddObject("Travels", travel);
     ctx.SaveChanges();
 }