Calculates a hash for an object in such a way that will not throw of affect the value if the object is null.

ObjectExtensions.cs

namespace Extensions
{
    /// <summary>
    /// Contains <see cref="object"/> extension methods.
    /// </summary>
    public static class ObjectExtensions
    {
        /// <summary>
        /// Calculates a hash for the object in such a way that will not throw or affect the value if the object is null.
        /// </summary>
        /// <param name="param">The param.</param>
        /// <param name="seed">The seed.</param>
        /// <returns>Hash.</returns>
        public static int NullSafeHash(this object param, int seed)
        {
            return null != param ? seed*7 + param.GetHashCode() : seed;
        }
    }
}