public void LoadData()
{
CategoryItems = System.Threading.Tasks.Task.Run(() => GetCategoryItems()).Result;
CategoryTasks = System.Threading.Tasks.Task.Run(() => GetCategoryTasks()).Result;
ItemList = System.Threading.Tasks.Task.Run(() => GetItems()).Result;
ItemList = new ObservableCollection <Item>(ItemList.Where(e => !CategoryItems.Contains(e)).ToList());
TaskList = System.Threading.Tasks.Task.Run(() => GetTasks()).Result;
TaskList = new ObservableCollection <Model.Task>(TaskList.Where(e => !CategoryTasks.Contains(e)).ToList());
}