不在哪里和哪里“或”问题 [英] Where not in and Where "Or" problem

问题描述

大家好，我在这篇文章中为我的问题找到了一半的解决方案：http://social.msdn.microsoft.com/forums/en-US/adodotnetentityframework/thread/095745fe-dcf0-4142-b684-b7e4a1ab59f0/

让我试着解释和说明我的问题。

公共类ClassEntityA 
 {
 public int Id {get;组; } 
 public string Text {get;组; } 
} 
 
公共类ClassEntityB 
 {
 public int Id {get;组; } 
 public string Text {get;组; } 
 public Nullable< ClassEntityA> EntityA {get;组; } 
} 
 
 
 //我需要在Ado Entity中执行以下查询。该查询在Linq To Sql中有效，但未在Linq To Entity中支持
 
 list< int> list = new List< in>（）{1,2,3}; 
 var itens = DbContext.ClassEntityB.Where（c =>（list.Contains（c.EntityA.Id）== false || c.EntityA == null）; 
 
 / /我在Linq To Entity中找到了半解决方案：
 
 //但在这里我可以进行第二次测试（或者c.EntityA == null）。我该怎么做？ 
 
 list< int> list = new List< in>（）{1,2,3}; 
 var itens = DbEntities.ClassEntityB.WhereNotIn（c => c.EntityA。 Id，list.AsEnumerable< int>（））
 
 
 #region不在
 
私有静态表达式< Func< TElement，bool>> 
 GetWhereNotInExpression< TElement，TValue>（
 Expression< Func< TElement，TValue>> propertySelector，
 IEnumerable< TValue> values）
 {
 ParameterExpression p = 
 propertySelector.Parameters.Single（）; 
 
 if（！values.Any（））
 {
 return e => true; 
 } 
 
 var unequals = values.Select（value => 
（表达式）Expression.NotEqual（
 propertySelector.Body，
 Expression.Constant（value，typeof（TValue））
）
）; 
 
 var body = unequals.Aggregate< Expression>（
（accumulate，unequal）=> Expression.And（accumulate，unequal））; 
 
返回Expression.Lambda< Func< TElement，bool>>（body，p）; 
} 
 
 public static IQueryable< TElement> 
 WhereNotIn< TElement，TValue>（此IQueryable< TElement>来源，
表达式< Func< TElement，TValue>> propertySelector，
 params TValue []值）
 {
返回source.Where（GetWhereNotInExpression（
 propertySelector，values））; 
} 
 
 public static IQueryable< TElement> 
 WhereNotIn< TElement，TValue>（此IQueryable< TElement>来源，
表达式< Func< TElement，TValue>> propertySelector，
 IEnumerable< TValue>值）
 {
返回source.Where（GetWhereNotInExpression（
 propertySelector，values））; 
} 
 
 #endregion 
 

你能帮助我吗？

我需要在Ado中进行查询，该查询中包含（"不在"或"Property == null"的测试）。

thx。

---

Luciano Correia

解决方案

任何小贴士？ PLZ

Hi guys,

i founf a half solution for my problem in that post: http://social.msdn.microsoft.com/forums/en-US/adodotnetentityframework/thread/095745fe-dcf0-4142-b684-b7e4a1ab59f0/

Let me try to explain and illustrate my problem.

public class ClassEntityA
{
    public int Id { get; set; }
    public string Text { get; set; }
}

public class ClassEntityB
{
    public int Id { get; set; }
    public string Text { get; set; }
    public Nullable<ClassEntityA> EntityA { get; set; }
}


// I need to do the following query in Ado Entity. That query works in Linq To Sql, but not suported in Linq To Entity

list<int> list = new List<in>() { 1, 2, 3 };
var itens = DbContext.ClassEntityB.Where(c => (list.Contains(c.EntityA.Id) ==  false || c.EntityA == null);

// i Found a Half Solution to do that in Linq To Entity doing that:

// But Here i can do the second test (OR c.EntityA == null). How can i do That?

list<int> list = new List<in>() { 1, 2, 3 };
var itens = DbEntities.ClassEntityB.WhereNotIn(c => c.EntityA.Id, list.AsEnumerable<int>())


 #region Where Not In

        private static Expression<Func<TElement, bool>>
            GetWhereNotInExpression<TElement, TValue>(
            Expression<Func<TElement, TValue>> propertySelector,
            IEnumerable<TValue> values)
        {
            ParameterExpression p =
                propertySelector.Parameters.Single();

            if (!values.Any())
            {
                return e => true;
            }

            var unequals = values.Select(value =>
                (Expression)Expression.NotEqual(
                    propertySelector.Body,
                    Expression.Constant(value, typeof(TValue))
                )
            );

            var body = unequals.Aggregate<Expression>(
                (accumulate, unequal) => Expression.And(accumulate, unequal));

            return Expression.Lambda<Func<TElement, bool>>(body, p);
        }

        public static IQueryable<TElement>
            WhereNotIn<TElement, TValue>(this IQueryable<TElement> source,
            Expression<Func<TElement, TValue>> propertySelector,
            params TValue[] values)
        {
            return source.Where(GetWhereNotInExpression(
                propertySelector, values));
        }

        public static IQueryable<TElement>
            WhereNotIn<TElement, TValue>(this IQueryable<TElement> source,
            Expression<Func<TElement, TValue>> propertySelector,
            IEnumerable<TValue> values)
        {
            return source.Where(GetWhereNotInExpression(
                propertySelector, values));
        }

        #endregion

Can any of you help me?

i need to do a Query in the Ado that have a ("Where not in" or "Property == null) teste.

thx.

---

Luciano Correia

解决方案

Any tips guys? plz

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