Equality Pattern from Resharper
I was just reading this blog entry on how Resharper can auto generate equality members.
This is a pretty nice pattern to follow even when doing this by hand.
Here is the class it was created for:
public class Fooberry
{
public string Foo { get; set; }
public string Bar { get; set; }
}
public override bool Equals(object obj) {
if (ReferenceEquals(null, obj)) return false;
if (ReferenceEquals(this, obj)) return true;
if (obj.GetType() != typeof (Fooberry)) return false;
return Equals((Fooberry) obj);
}
public bool Equals(Fooberry obj)
{
if (ReferenceEquals(null, obj)) return false;
if (ReferenceEquals(this, obj)) return true;
return Equals(obj.Foo, Foo) && Equals(obj.Bar, Bar);
}
public override int GetHashCode()
{
unchecked
{
return ((Foo != null ? Foo.GetHashCode() : 0)*397) ^ (Bar != null ? Bar.GetHashCode() : 0);
}
}
I’ve know about most of this pattern including ReferenceEquals, but look at the unchecked keyword. Very cool indeed. I do wonder what the significance of the ‘* 397’ is though. Any ideas?
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