LINQ 動的に条件を追加する

    public class LinqHelper
    {
        /// <summary>
        /// 動的にLINQ条件を追加する
        /// </summary>
        /// <typeparam name="T">IQueryable</typeparam>
        /// <typeparam name="C">Expression.Constant</typeparam>
        /// <param name="queryable">クエリ原型</param>
        /// <param name="property">プロパティ名</param>
        /// <param name="constant">Value</param>
        /// <returns>IQueryable</returns>
        public IQueryable<T> AddParameterExpression<T, C>(IQueryable<T> queryable, string property, C constant)
        {
            ParameterExpression parameterExpression = Expression.Parameter(typeof(T), "param");

            Expression<Func<T, bool>> ex = Expression.Lambda<Func<T, bool>>(
                Expression.Equal(
                        Expression.Property(parameterExpression, typeof(T).GetProperty(property)),
                        Expression.Constant(constant, typeof(C)),
                        false,
                        typeof(T).GetMethod("op_Equality")
                ),
                new ParameterExpression[] { parameterExpression }
            );

            return queryable.Where(ex);
        }
    }
}