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C# Intermediate C# System.Object Object.Equals

Posted by Ryan Pierson
Ryan Pierson
14,365 Points

override Object.GetHashCode()?

I'm getting the following error when trying to override the Object.Equals()?

`TreehouseDefense.Point' overrides Object.Equals(object) but does not override Object.GetHashCode()

function still doesn't work when ran.

Snapshot: https://w.trhou.se/txmpccffb2

1 Answer

Christopher Coscina
Christopher Coscina
5,611 Points
Christopher Coscina
Christopher Coscina
5,611 Points

According to Microsoft Docs:

Derived classes that override GetHashCode() must also override Equals(Object) to guarantee that two objects considered equal have the same hash code; otherwise, the Hashtable type might not work correctly. https://docs.microsoft.com/en-us/dotnet/api/system.object.gethashcode?view=netframework-4.7.2

In a nutshell, GetHashCode is used in things like dictionaries (it doesn't use the object itself as the key, but rather a "hash code" which is much more lightweight and more efficient than a big clunky object). A hash code should uniquely identify an object to prevent "collisions" in which two objects that aren't equal can have the same hash code. If two objects are equal, their hash code should be the same and if two objects are not equal their hash code should not be the same. Therefore the Equals and GetHashCode methods are closely related.