List.Contains is not working as hoped

Question

If I have an object of type MyBull and a List orig:

// Just an example
MyBull x = getMeTheObjectWithIdFromDB(9);

ori         


        

Answer 1

This is because the MyBull instances are being compared by reference. From the point of view from .NET, x and y are both different instances and therefore not Equal.

In order to get around this you will have to override the Equals and GetHashCode methods (which means you should probably implement IEquatable and override the == and != operators too).