Generates a hashcode for simple objects that depends on its contents.

gistfile1.cs

    public class HashCodeGenerator<T>
    {
        private readonly List<Func<T, object>> _getters = new List<Func<T, object>>();

        public HashCodeGenerator()
        {
            PropertyInfo[] properties = typeof(T).GetProperties();

            foreach (var p in properties)
            {
                Func<T, object> getter = GetValueGetter<T>(p);
                _getters.Add(getter);
            }
        }

        public int Generate(T o)
        {
            int hashCode = 0;

            foreach (var getter in _getters)
            {
                object value = getter(o);
                hashCode = (hashCode * 397) ^ (value != null ? value.GetHashCode() : 0);
            }

            return hashCode;
        }

        private static Func<T, object> GetValueGetter<T>(PropertyInfo propertyInfo)
        {
            ParameterExpression instance = Expression.Parameter(propertyInfo.DeclaringType, "i");
            MemberExpression property = Expression.Property(instance, propertyInfo);
            UnaryExpression convert = Expression.TypeAs(property, typeof(object));
            return Expression.Lambda<Func<T, object>>(convert, instance).Compile();
        }
    }