我是很新，
Linq和EF
您很不走运，因为“简单的事情”在LINQ to Objects中相对容易，但是在LINQ to Entities中却相当困难（几乎不可能）。
为了以某种方式解决它，您需要手动构建LINQ to Entitiescompatible
expression。
首先，您需要一些帮助程序来构建表达谓词。PredicateBuilder是一个流行的选择，但它不会产生EF兼容表情和要求
LinqKit，并
AsExpandable在仓库里。因此，我使用以下类似的辅助方法，但会产生最终的兼容表达式：
public static class PredicateUtils{ sealed class Predicate<T> { public static readonly expression<Func<T, bool>> True = item => true; public static readonly expression<Func<T, bool>> False = item => false; } public static expression<Func<T, bool>> Null<T>() { return null; } public static expression<Func<T, bool>> True<T>() { return Predicate<T>.True; } public static expression<Func<T, bool>> False<T>() { return Predicate<T>.False; } public static expression<Func<T, bool>> And<T>(this expression<Func<T, bool>> left, expression<Func<T, bool>> right) { if (Equals(left, right)) return left; if (left == null || Equals(left, True<T>())) return right; if (right == null || Equals(right, True<T>())) return left; if (Equals(left, False<T>()) || Equals(right, False<T>())) return False<T>(); var body = expression.AndAlso(left.Body, right.Body.Replace(right.Parameters[0], left.Parameters[0])); return expression.Lambda<Func<T, bool>>(body, left.Parameters); } public static expression<Func<T, bool>> Or<T>(this expression<Func<T, bool>> left, expression<Func<T, bool>> right) { if (Equals(left, right)) return left; if (left == null || Equals(left, False<T>())) return right; if (right == null || Equals(right, False<T>())) return left; if (Equals(left, True<T>()) || Equals(right, True<T>())) return True<T>(); var body = expression.OrElse(left.Body, right.Body.Replace(right.Parameters[0], left.Parameters[0])); return expression.Lambda<Func<T, bool>>(body, left.Parameters); } static expression Replace(this expression expression, expression source, expression target) { return new expressionReplacer { Source = source, Target = target }.Visit(expression); } class expressionReplacer : expressionVisitor { public expression Source; public expression Target; public override expression Visit(expression node) { return node == Source ? Target : base.Visit(node); } }}其次，在控制器中为这样的单个条件定义一个辅助方法
static expression<Func<Person, bool>> AbilityFilter(int index, int value){ return p => p.AllAbilities.OrderBy(a => a.Id).Skip(index).Take(1).Any(a => a.Value > value);}最后，构建过滤器并将其传递给
GetAll方法：
var filter = PredicateUtils.Null<Person>();for (int i = 0; i < AbilitiesInput.Count; i++) filter = filter.And(AbilityFilter(i, AbilitiesInput[i]));GetAll(filter);
使用的技术绝对不是新手，但我认为没有简单的方法可以解决该特定问题。
