[C#] Problems with with List.Sort()

Unity Engine
1

Hello guys!

I’m sure the solution of this problem will be pretty simple, but after a lot of research I just can’t make it work. I’m an amateur Unity/C# user, and I don’t quite understand what MSDN says ab

I have a list containing 3 different variables, and what I want to do is simply reorder it with descending “Speed” variable.

	public class ActionOrder:IComparer <ActionOrder> {
		
		public int CharacterCounter;
		public int Speed;
		public bool EnemyAction;
		
		public ActionOrder (int CharacterCounter, int Speed, bool EnemyAction){
			this.CharacterCounter = CharacterCounter;
			this.Speed = Speed;
			this.EnemyAction = EnemyAction;
		}

		public int Compare (ActionOrder a, ActionOrder b){
			if (a.Speed > b.Speed)
				return 1;
			else if (a.Speed < b.Speed)
				return -1;
			else return 0;
		}
	}

	public List<ActionOrder> actionOrder = new List<ActionOrder>();

	void Start (){

		Debug.Log (actionOrder[0].Speed);
		Debug.Log (actionOrder[1].Speed);
		Debug.Log (actionOrder[2].Speed);
		Debug.Log (actionOrder[3].Speed);

		actionOrder.Sort();
		
		Debug.Log (actionOrder[0].Speed);
		Debug.Log (actionOrder[1].Speed);
		Debug.Log (actionOrder[2].Speed);
		Debug.Log (actionOrder[3].Speed);

	}

This code results in this error, which I also couldn’t figure out what exactly it means:
“ArgumentException: does not implement right interface” and a giant log…

Also, if there’s a simpler method for sorting Lists I would appreciate if you share it.

Cheers!

2

IIRC the class needs to implement IComparable which has a CompareTo(T other) method in order for Sort with no arguments to work correctly. There is also an overload of Sort that takes a delegate in the event your class doesn’t implement that interface with the expectation that you mimic the interfaces functionality in that delegate.

3

I’m sorry, my knowlege is not good enough to understand what you’re saying…

You’re suggesting me to use IComparable instead of IComparer, is that it? I tried, but when I implemented “using System” it broke the rest of my code (mainly the "Random"s).

4

That seems…odd - but in any case you can just qualify that specific line if you want.

public class ActionOrder : System.IComparable<ActionOrder>
{
    public int CompareTo(ActionOrder other) { ... }
}
5

Yeah! That worked, thank you sir!