private void FillTasks() { Tasks = new ObservableCollection <LabDetailTask>(); context.GetTasksOfLab(LabID).ForEach(t => { context.GetTaskDonesOfTask(t.taskID).ForEach(tD => { var s = context.GetStudentOfTaskDone(tD.taskDoneID); Tasks.Add(new LabDetailTask { // student StudentID = s.studentID, FirstName = s.firstName, LastName = s.lastName, MatricelNumber = s.matricelNumber, // task TaskID = t.taskID, TaskNumber = t.taskNumber, DueDate = t.dueDate, // taskDone TaskDoneID = tD.taskDoneID, IsDone = Convert.ToBoolean(tD.isDone) });; }); }); LabTaskCount = Tasks.Count; }