Warning: "... overrides Object.Equals(object o) but does not override Object.GetHashCode()"

I overrode the Equals() of my class to compare ID values of type Guid.

Then Visual Studio warned:

... overrides Object.Equals(object o) but does not override Object.GetHashCode()

So I then also overrode its GetHashCode() like this:

public partial class SomeClass
{
    public override bool Equals(Object obj)
    {
        //Check for null and compare run-time types.
        if (obj == null || this.GetType() != obj.GetType()) return false;

        return this.Id == ((SomeClass)obj).Id;
    }

    public override int GetHashCode()
    {
        return this.Id.GetHashCode();
    }
}

It seems to work. Have I done this correctly? Remember Id is of type Guid. Does it matter that my class is an Entity Framework object?