Add List<DateTime> values inside a List<T>

Question

This might be kind of Tricky. Basically I've got a class that looks like this:

class Timer
{
    public string boss { get; set; }
    public List<DateTime> spawnTimes { get; set; }
    public TimeSpan Runtime { get; set; }
    public BossPriority priority { get; set; }

}

As you can see, I want to add a list of DateTimes in my object. So I've created a list that looks like this:

List<Timer> bosses = new List<Timer>();

I was hoping that I could do something similar to this, to add the DateTimes:

bosses.Add(new Timer { boss = "Tequatl", priority = BossPriority.HardCore, spanTimes = {  DateTime.ParseExact("07:00 +0000", "hh:mm zzz", CultureInfo.InvariantCulture) } });

Unfortunately, that is giving me a "Object reference not set to an instance of an object." error.

Doing it like this, doesn't make a difference either :(

Timer boss = new Timer();
DateTime t1 = DateTime.ParseExact("07:00 +0000", "hh:mm zzz", CultureInfo.InvariantCulture);
DateTime t2 = DateTime.ParseExact("11:30 +0000", "hh:mm zzz", CultureInfo.InvariantCulture);
boss.spawnTimes.AddRange(new List<DateTime> { t1, t2 });

Do I really have do .Add() on every DateTime?

Answer 1

Your NRE is caused by the fact you're not initializing Timer.spawnTimes.

You can save on typing if you initialize the class as part of the default constructor:

public class Timer {

    public List<DateTime> SpawnTimes { get; private set; }
    ...

    public Timer() {
        this.SpawnTimes = new List<DateTime>();
    }

}

Another option is to have an overloaded constructor that accepts params arguments:

public class Timer {

    public List<DateTime> SpawnTimes { get; private set; }
    ...

    public Timer() {
        this.SpawnTimes = new List<DateTime>();
    }

    public Timer(String boss, /*String runtime,*/ BossPriority priority, params String[] spawnTimes) : this() {

        this.Boss = boss;
//      this.Runtime = TimeSpan.Parse( runtime );
        this.Priority = priority;

        foreach(String time in spawnTimes) {

            this.SpawnTimes.Add( DateTime.ParseExact( time, "HH:mm" ) );
        }

    }
}

This is used in practice like so:

bosses.Add( new Timer("Tequat1", BossPriority.HardCore, "07:00 +0000" ) );
bosses.Add( new Timer("Tequat2", BossPriority.Nightmare, "01:00 +0000", "01:30 +0000" ) );
bosses.Add( new Timer("Tequat3", BossPriority.UltraViolence, "12:00 +0000" ) );

Also: FxCop/StyleCop time!

• Types (like classes) should be PascalCase
• Public members should also be PascalCase (unlike in Java where they're camelCase)
  • e.g. public BossPriority priority should be public BossPriority Priority
• Collection members should not be exposed through mutable properties (i.e. use private set instead of set (implied public)
• Public collection members should be Collection<T> or ReadOnlyCollection<T> instead of List<T> or T[]

Answer 2

You're close... you just forgot to declare a new instance.

Add new[] and then cast the the array to a List:

bosses.Add(new Timer { boss = "Tequatl", priority = BossPriority.HardCore,
    spawnTimes = new[] { DateTime.ParseExact("07:00 +0000", "hh:mm zzz", CultureInfo.InvariantCulture) }.ToList() });