Question

I am sure if I override Equals, I need to override GetHashCode as well to make sure Dictionary, etc. data structures work as expected.

But if I just want to override ToString, do I still have to override Equals and GetHashCode methods?

Answer 1

Overriding those three methods serve three different purposes:

1. ToString: Output representation of the object.
2. Equals: If two objects represent the same thing. It uses GetHashCode in its default implementation.
3. GetHashCode: Used for indexing of objects. Several advanced topics here including semi-uniqueness and distribution of hashvalues.

As you can see, 2 and 3 are related, but 1 is separate. Unless you implement Equals to simply test if the ToString of two objects are equals, which would most likely be a mistake. 🙂

So the short answer has already been given: You can override ToString without overriding the two other methods. It is quite normal to even overload the ToString method. See DateTime for an example: DateTime.ToString Method