Can't update area of a test case programatically

Question

I'm trying to update the area of a test case programatically.

The code I have seems logical, but fails with:

An unhandled exception of type 'Microsoft.TeamFoundation.WorkItemTracking.Client.ValidationException' occurred in Microsoft.TeamFoundation.WorkItemTracking.Client.dll

Additional information: TF400276: You have tried to set a value for a field of a work item which is not opened or partial opened. You cannot set a value for a field of a work item which is not opened or partial opened.

Here is the code:

private static void Main(string[] args)
      {
         TeamProjectPicker tpp = new TeamProjectPicker(TeamProjectPickerMode.SingleProject, false);
         tpp.ShowDialog();

         var tc = TfsTeamProjectCollectionFactory.GetTeamProjectCollection(
                                                                           tfsUri,
            new UICredentialsProvider());

         tc.EnsureAuthenticated();

         var wiStore = tc.GetService<TestManagementService>();

         var project = wiStore.GetTeamProject(tpp.SelectedProjects[0].Name);

         SetAreaPathByTestSuiteID(project, 501);



      }

      private static void SetAreaPathByTestSuiteID(ITestManagementTeamProject project, int testSuiteID)
      {
         var testSuite = project.TestSuites.Find(testSuiteID).TestCases;

         foreach (ITestSuiteEntry entry in testSuite)
         {
            ITestCase theCase = entry.TestCase;
            theCase.Area = "NewAreaPath"; //Error thrown here
            theCase.Save();

         }
      }

Answer 1

I know this thread is old, but I'll answer it anyway, in case someone encounters the same problem. To be able to edit a test case, you should call Open() like this:

theCase.WorkItem.Open();

And that's it.

Answer 2

You should just call a WorkItem. That's enough if you

 testCase.WorkItem.PartialOpen();

if you call

 testCase.WorkItem.Open();

then Save, you will to override the steps and parameter value