SetOriginalRowVersion.cs

// method to add to dbcontext

        /// <summary>
        /// Set EF's OriginalValue of RowVersion for 'entity' to the supplied value.
        /// This allows you to make use of EF's built-in concurrent-editing
        /// when you don't have the entity as it was presented to the user to
        /// edit (because of the stateless nature of the web).
        /// Call this before SaveChanges to ensure concurrent edits don't go
        /// unnoticed by users.
        /// More info: http://stackoverflow.com/a/9190378/10245
        /// </summary>
        /// <typeparam name="TEntity">The type of the entity.</typeparam>
        /// <param name="entity">The entity for which you want to change the source row version in EF's original value cache.</param>
        /// <param name="value">The new value for the original row version.</param>
        public void SetOriginalRowVersion<TEntity>(TEntity entity, byte[] value) where TEntity : class
        {
            Entry(entity).OriginalValues["RowVersion"] = value;
        }