从 c# 中的多级集合中删除项目

Question

I have a multilevel collection such as

public class Year
{
    public IList<Month> months { get; set; }
}

public class Month
{
    public IList<Day> days { get; set; }
}
public class Day
{
    public IList<Hour> hour { get; set; }
}
public class Hour
{
    public bool IsWorkinghour { get; set; }
    // some other properties here   
}

Here Year contain a list of months, and months contain a list of day, same days contain a list of hours, its a 4 level collection. In an object of type "Year", I want to remove hours where Isworkinghour is false, and also if all hours are set as false under a day than remove that day also. Below is my code for that.

var year = new Year();
        if(year != null && year.months.Count() > 0)
        {
            foreach(var m in year.months.ToList())
            {
                foreach(var d in m.days.ToList())
                {
                    foreach(var h in d.hour.ToList())
                    {
                        if(!h.IsWorkinghour)
                        {
                            d.hour.Remove(h);
                        }
                    }
                    if(d.hour.Count == 0)
                    {
                        m.days.Remove(d);
                    }
                }
            }
        }

Can someone please let me know where is the mistake in this as it does not remove the items, Thanks.

Answer 1

If you don't want to use .ToList() ,you can put new data to new Year():

var newyear= new Year();
if (year != null && year.months.Count() > 0)
{
    List<Month> months = new List<Month>();
    foreach (var m in year.months)
    {
        List<Day> days = new List<Day>();
        foreach (var d in m.days)
        {
            List<Hour> hours = new List<Hour>();
            foreach (var h in d.hour)
            {
                if (h.IsWorkinghour)
                {
                    hours.Add(h);
                }
            }
            if (hours.Count() > 0)
            {
                days.Add(new Day { hour = hours });
            }
        }
        months.Add(new Month { days = days });
    }
    newyear.months = months;
}

Answer 2

Your code looks fine from a logical view. You could use lambda expression to compress your code if you want to.

// remove all hours where IsWorkinghour is true
year.months.ToList().ForEach(x => x.days.ToList().ForEach(y => y.hour.ToList().RemoveAll(z => z.IsWorkinghour)));
    
// remove all days that doesn't contain any hours
year.months.ToList().ForEach(x => x.days.ToList().RemoveAll(y => y.hour.Count == 0));

This lambda expression expects that all lists in the Year Object are at least initialized.