You can override the Equals method in a custom type to implement value equality for two instances of the type.
Guidelines to follow when overriding Equals include:
- x.Equals(x) should return true
- x.Equals(y) should return the same value as y.Equals(x)
- x.Equals(y) and y.Equals(z) implies that x.Equals(z)
- Repeated calls to x.Equals(y) return the same result, for the same values of x and y
- x.Equals(null) returns false
Additionally:
- When you override Equals, you should also override GetHashCode
Here’s the implementation of Equals for the Dog class:
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| // Are two Dogs equivalent?public override bool Equals(object obj){ // Can't be null if (obj == null) return false; // Must be a Dog if (obj is Dog) { // Compare the dogs Dog d2 = (Dog)obj; return (Name == d2.Name) && (Age == d2.Age); } else return false;} |
Here’s the override of GetHashCode.
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| public override int GetHashCode(){ return Name.GetHashCode() ^ Age;} |