private void Update(TestSolution testSolution)
 {
     if (testSolution != null)
     {
         if (TestSolution == null)
         {
             TestSolution = new TestSolutionViewModel(testSolution);
         }
         else
         {
             TestSolution.UpdateItem(testSolution);
         }
     }
     else
     {
         TestSolution = null;
     }
 }