When should you use C# indexers?

Question

I\'d like to use indexers more, but I\'m not sure when to use them. All I\'ve found online are examples that use classes like MyClass and IndexerClass

Answer 1

Indexer is a highly specialized property which allows instances of a class (or struct) to be indexed just like an array(properties can be static but indexers cannot).

Why use indexers:
- instead of a new data structure, the class itself is a data structure.
- simplified syntax - syntactic sugar

When to use:
- if your class needs list(/array) of its instances (example 1)
- if your class represents list(/array) of values directly related to your class (example 2)

Example 1:

public class Person{
    public string Name{get; set;}

    private Person[] _backingStore;
    public Person this[int index]
    {
        get{
            return _backingStore[index];
        }
        set{
            _backingStore[index] = value;
        }
    }
}

Person p = new Person();
p[0] = new Person(){Name = "Hassan"};
p[1] = new Person(){Name = "John Skeet"};    

Example 2:

class TempratureRecord{
    private float[] temps = new float[10] { 56.2F, 56.7F, 56.5F, 56.9F, 58.8F, 61.3F, 56.5F, 56.9F, 58.8F, 61.3F};

    public int Length{
        get { return temps.Length; }
    }

    public float this[int index]
    {
        get{
            return temps[index];
        }
        set{
            temps[index] = value;
        }
    }
}