public TaskGroupModel(DateTime rangeStart, DateTime rangeEnd,
ICollection <ITask> tasks, IPreferences preferences)
{
if (preferences == null)
{
throw new ArgumentNullException("preferences");
}
if (tasks == null)
{
throw new ArgumentNullException("tasks");
}
this.timeRangeStart = rangeStart;
this.timeRangeEnd = rangeEnd;
taskChangeLog = new List <MementoTask> ();
showCompletedTasks = preferences.GetBool(
PreferencesKeys.ShowCompletedTasksKey);
originalTasks = tasks;
((INotifyCollectionChanged)tasks).CollectionChanged += HandleCollectionChanged;
// register change events for each task
foreach (var item in tasks)
{
item.PropertyChanging += HandlePropertyChanging;
item.PropertyChanged += HandlePropertyChanged;
}
}