#417 – Provide a Type-Specific Equals Method for Value Equality

When you are implementing value equality in a type, you typically override the Equals method that is defined in System.Object.  It has the following signature:

        public override bool Equals(object obj)

You should also add a type-specific Equals method.  For completeness, you can indicate that your class implements IEquatable<T>, which includes the type-specific Equals method.

    public class Dog : IEquatable<Dog>

Below is a complete example, showing us the override of System.Object.Equals, as well as the type-specific Equals method.  Note that the generic Equals method calls the type-specific version.

        // System.Object.Equals
        public override bool Equals(object obj)
        {
            return this.Equals(obj as Dog);
        }

        // IEquatable<Dog>.Equals
        public bool Equals(Dog d)
        {
            if (d == null)
                return false;

            return (Name == d.Name) && (Age == d.Age);
        }