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  • EF中扩展出Between操作符 (修订版)

    随手记录一下,这是针对原文错误的修改。

    原文:EF中扩展出Between操作符

    直接使用是错误的,修改后的扩展方法:

    /// <summary>
            /// 扩展 Between 操作符
            /// 使用 var query = db.People.Between(person => person.Age, 18, 21);
            /// </summary>
            /// <typeparam name="TSource"></typeparam>
            /// <typeparam name="TKey"></typeparam>
            /// <param name="source"></param>
            /// <param name="keySelector"></param>
            /// <param name="low"></param>
            /// <param name="high"></param>
            /// <returns></returns>
            public static IQueryable<TSource> Between<TSource, TKey>(this IQueryable<TSource> source,
                    Expression<Func<TSource, TKey>> keySelector,
                    TKey low,
                    TKey high) where TKey : IComparable<TKey>
            {
                Expression key = Expression.Invoke(keySelector, keySelector.Parameters.ToArray());
                Expression lowerBound = Expression.GreaterThanOrEqual(key, Expression.Constant(low));
                Expression upperBound = Expression.LessThanOrEqual(key, Expression.Constant(high));
                Expression and = Expression.AndAlso(lowerBound, upperBound);
                Expression<Func<TSource, bool>> lambda = Expression.Lambda<Func<TSource, bool>>(and, keySelector.Parameters);
                return source.Where(lambda.Compile()).AsQueryable();
            }
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  • 原文地址:https://www.cnblogs.com/likeli/p/5856211.html
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