//add an item to todo list
public void AddItem(SubTaskToDoList subTaskToDo)
{
if (subTaskToDo is null)
{
throw new ArgumentNullException(nameof(subTaskToDo));
}
subTasks.Add(subTaskToDo);
}
//Add a task as Completed Task which has sub tasks
public void CompleteSubTask(ToDoListItem toDoListItem, SubTaskToDoList subTaskTo)
{
if (toDoListItem is null)
{
throw new ArgumentNullException(nameof(toDoListItem));
}
if (toDoListItem.IsCompleted == true & subTaskTo.HasSubTask == false)
{
tasks.Add(toDoListItem);
}
if (subTaskTo.HasSubTask == true)
{
foreach (var item in subTaskTo.GetAllSubTasks())
{
if (item.IsCompleted == true)
{
tasks.Add(subTaskTo);//if every sub task items completed only main task consider as completed task
}
}
}
}