Linq 到实体并包含？

Question

嗨，

我有一个像这样的 linq to sql 问题：

tmpAdList1 = (from p in context.Ads
                            join h in context.AdCategories on p.CategoryId equals h.Id
                            join l in context.Location on p.UserLocationId equals l.Id
                            where
                            (adList.S == null || adList.S.Length < 1 || p.Title.Contains(adList.S) || p.Description.Contains(adList.S)) &&
                            (categorylevelOrder.Length < 1 || h.LevelOrder.StartsWith(categorylevelOrder)) &&

                            ((locationIdList != null && lList.Contains(l.Id)) ||
                            (locationLevelOrder.Length < 1 || l.LevelOrder.StartsWith(locationLevelOrder))) &&

                            ((adTypeO1 == AdType.Unknown && adTypeO2 == AdType.Unknown && adTypeO3 == AdType.Unknown && adTypeO4 == AdType.Unknown && adTypeO5 == AdType.Unknown) ||
                            (p.TypeOfAd == (int)adTypeO1 || p.TypeOfAd == (int)adTypeO2 || p.TypeOfAd == (int)adTypeO3 || p.TypeOfAd == (int)adTypeO4 || p.TypeOfAd == (int)adTypeO5)) && //Check for default filters
                            ((AdListShowType)adList.ALS.ST == AdListShowType.Both || adList.ALS.ST == p.OwnerType) &&
                            (p.PublishedDate.HasValue && p.PublishedDate.Value.CompareTo(fetchAdsTo) >= 1) &&
                            ((adOwnerType1.HasValue && adOwnerType2.HasValue) || p.OwnerType == (int)adOwnerType1.Value) &&
                            p.InactivatedDate == null
                            orderby p.CreatedDate descending
                            select p).ToList();

请参阅 Edit1 了解整个方法

运行此问题后，将进行更多过滤（在上下文中），但要尽可能快地完成第一个问题，我的目标是从 SQL 服务器获取尽可能少的记录。

问题是我需要将 int[] 的 locationIdList 与实体进行比较。抛出的异常是：

无法比较“System.Int32[]”类型的元素。仅支持原始类型（例如 Int32、String 和 Guid）和实体类型。

我在 google 上搜索了该问题，这是一个已知问题，但是我发现了这样的示例：

var list = new List<int> { 1, 2, 3, 5 };
var result = from s in DB.Something
             where list.Contains(s.Id)
             select s;

但这会引发相同的异常？我还读到存储过程可以解决问题，但我还没有找到它是如何工作的？

有什么建议吗？

BestRegards

编辑 1： 整个方法：

public List<Ad> GetAds(AdList adList, DateTime fetchAdsTo, out int totalAds)
{
    AdType adTypeO1 = AdType.Unknown;
    AdType adTypeO2 = AdType.Unknown;
    AdType adTypeO3 = AdType.Unknown;
    AdType adTypeO4 = AdType.Unknown;
    AdType adTypeO5 = AdType.Unknown;

    int? adOwnerType1 = null;
    int? adOwnerType2 = null;

    FilterModel filterModel = new FilterModel();

    List<AdCategoryFilter> adCategoryFilterList;
    AdsFilterValues adsFilterValues;
    List<AdsFilterValueWrapper> seartchFilterValueList;
    AdsFilterValueWrapper seartchFilterValue = null;
    List<Ad> tmpAdList1;
    List<Ad> tmpAdList2 = new List<Ad>();

    int locationId = -1;
    int[] locationIdList = null;
    string locationLevelOrder = string.Empty;

    int categoryId = -1;
    string categorylevelOrder = string.Empty;

    AdCategoryFilter adCategoryFilter;

    AdListCompare adListCompare;

    Boolean firstDropDownMatch = false;
    Boolean secondDropDownMatch = false;

    totalAds = 0;

    int machedFilterCount;

    categoryId = AdHandler.Instance.ExtractCategoryId(adList.CS);

    //If there is multiple choises
    //This is the last level, that means that we can check against the ID dircly
    if (adList.LS.L3.Count > 0)
        locationIdList = adList.LS.L3.ToArray();
    else
        locationId = AdHandler.Instance.ExtractLocationId(adList.LS);


    switch ((AdOwnerType)adList.ALS.ST)
    {
        case AdOwnerType.Both:
            adOwnerType1 = (int)AdOwnerType.Private;
            adOwnerType2 = (int)AdOwnerType.Company;
            break;
        case AdOwnerType.Company:
            adOwnerType1 = (int)AdOwnerType.Company;
            break;
        case AdOwnerType.Private:
            adOwnerType1 = (int)AdOwnerType.Private;
            break;
    }

    #region GetFilters
    adCategoryFilterList = filterModel.GetCategoryFilterByCategory(categoryId);
    seartchFilterValueList = FilterHandler.Instance.ConvertAdFilterToModel(adList.F, adCategoryFilterList, FilterType.Display);
    #endregion

    #region Set Default filters (Buy, Let, Sell, Swap, WishRent)
    foreach (AdsFilterValueWrapper filterWrapper in seartchFilterValueList)
    {
        if ((adCategoryFilter = adCategoryFilterList.Where(c => c.Id == filterWrapper.FilterId).FirstOrDefault()) != null)
        {
            switch ((PublicAdFilterKey)adCategoryFilter.PublicAdFilterKey)
            {
                case PublicAdFilterKey.Buy:
                    {
                        if (filterWrapper.AdsFilterValues1.ValueNumber > 0)
                            adTypeO1 = AdType.Buy;
                        break;
                    }
                case PublicAdFilterKey.Let:
                    {
                        if (filterWrapper.AdsFilterValues1.ValueNumber > 0)
                            adTypeO2 = AdType.Let;
                        break;
                    }
                case PublicAdFilterKey.Sell:
                    {
                        if (filterWrapper.AdsFilterValues1.ValueNumber > 0)
                            adTypeO3 = AdType.Sell;
                        break;
                    }
                case PublicAdFilterKey.Swap:
                    {
                        if (filterWrapper.AdsFilterValues1.ValueNumber > 0)
                            adTypeO4 = AdType.Swap;
                        break;
                    }
                case PublicAdFilterKey.WishRent:
                    {
                        if (filterWrapper.AdsFilterValues1.ValueNumber > 0)
                            adTypeO5 = AdType.WishRent;
                        break;
                    }
            }
        }
    }

    #region Remove default filters fom filterList
    adCategoryFilterList = adCategoryFilterList.Where(c => ((PublicAdFilterKey)c.PublicAdFilterKey) != PublicAdFilterKey.Buy &&
                                    ((PublicAdFilterKey)c.PublicAdFilterKey) != PublicAdFilterKey.Let &&
                                    ((PublicAdFilterKey)c.PublicAdFilterKey) != PublicAdFilterKey.Sell &&
                                    ((PublicAdFilterKey)c.PublicAdFilterKey) != PublicAdFilterKey.Swap &&
                                    ((PublicAdFilterKey)c.PublicAdFilterKey) != PublicAdFilterKey.WishRent).ToList();
    #endregion
    #endregion

    var lList = adList.LS.L3.ToList<int>(); //new List<int> { 1, 2, 3, 5 };


    using (BissEntities context = new BissEntities())
    {
        if (categoryId > 0)
            categorylevelOrder = context.AdCategories.Where(c => c.Id.Equals(categoryId)).FirstOrDefault().LevelOrder.Trim();
        if (locationId > 0)
            locationLevelOrder = context.Location.Where(c => c.Id.Equals(locationId)).FirstOrDefault().LevelOrder.Trim();

        tmpAdList1 = (from p in context.Ads
                        join h in context.AdCategories on p.CategoryId equals h.Id
                        join l in context.Location on p.UserLocationId equals l.Id
                        where
                        (adList.S == null || adList.S.Length < 1 || p.Title.Contains(adList.S) || p.Description.Contains(adList.S)) &&
                        (categorylevelOrder.Length < 1 || h.LevelOrder.StartsWith(categorylevelOrder)) &&

                        ((locationIdList != null && lList.Contains(l.Id)) ||
                        (locationLevelOrder.Length < 1 || l.LevelOrder.StartsWith(locationLevelOrder))) &&

                        ((adTypeO1 == AdType.Unknown && adTypeO2 == AdType.Unknown && adTypeO3 == AdType.Unknown && adTypeO4 == AdType.Unknown && adTypeO5 == AdType.Unknown) ||
                        (p.TypeOfAd == (int)adTypeO1 || p.TypeOfAd == (int)adTypeO2 || p.TypeOfAd == (int)adTypeO3 || p.TypeOfAd == (int)adTypeO4 || p.TypeOfAd == (int)adTypeO5)) && //Check for default filters
                        ((AdListShowType)adList.ALS.ST == AdListShowType.Both || adList.ALS.ST == p.OwnerType) &&
                        (p.PublishedDate.HasValue && p.PublishedDate.Value.CompareTo(fetchAdsTo) >= 1) &&
                        ((adOwnerType1.HasValue && adOwnerType2.HasValue) || p.OwnerType == (int)adOwnerType1.Value) &&
                        p.InactivatedDate == null
                        orderby p.CreatedDate descending
                        select p).ToList();

        #region Filter collection
        foreach (Ad ad in tmpAdList1)
        {
            machedFilterCount = 0;
            adListCompare = AdListCompare.NotCompered;

            if (adCategoryFilterList.Count > 0)
            {                     
                //Loop the filters that belongs to the choosen category
                foreach (AdCategoryFilter existingFilter in adCategoryFilterList)
                {
                    //Se if the ad has the proper filter If not return it
                    if ((adsFilterValues = ad.AdsFilterValues.Where(c => c.CategoryFilterId == existingFilter.Id).FirstOrDefault()) != null || existingFilter.PublicAdFilterKey > 0)
                    {

                        //If the filter is not a regular value filter but a filter pointed to a property on the ad
                        //Then extract the correct value and use it
                        if (existingFilter.PublicAdFilterKey > 0)
                        {
                            adsFilterValues = new AdsFilterValues();
                            adsFilterValues.CategoryFilterId = existingFilter.Id;

                            switch ((PublicAdFilterKey)existingFilter.PublicAdFilterKey)
                            {
                                case PublicAdFilterKey.Price:
                                    {
                                        adsFilterValues.ValueNumber = ad.Price;
                                        break;
                                    }
                            }

                        }

                        if ((seartchFilterValue = seartchFilterValueList.Where(c => c.AdsFilterValues1.CategoryFilterId == adsFilterValues.CategoryFilterId).FirstOrDefault()) != null)
                        {
                            firstDropDownMatch = false;
                            secondDropDownMatch = false;
                            adListCompare = AdListCompare.Compared;

                            switch ((FilterControlType)existingFilter.DisplayFilterControlType)
                            {
                                case FilterControlType.TwoDropDown:

                                    //Check so the first dropdown value compare
                                    //If the index is the first then any value will do
                                    if (seartchFilterValue.FilterIndexPosition1 == FilterIndexPosition.First)
                                        firstDropDownMatch = true;
                                    else
                                    {
                                        if (adsFilterValues.ValueNumber.Value >= seartchFilterValue.AdsFilterValues1.ValueNumber.Value)
                                            firstDropDownMatch = true;
                                    }

                                    if (firstDropDownMatch)
                                    {
                                        //Check so the second dropdown value compare
                                        //If the index is the last then any value will do
                                        if (seartchFilterValue.FilterIndexPosition2 == FilterIndexPosition.Last)
                                            secondDropDownMatch = true;
                                        else
                                        {
                                            if (adsFilterValues.ValueNumber.Value <= seartchFilterValue.AdsFilterValues2.ValueNumber.Value)
                                                secondDropDownMatch = true;
                                        }

                                        if (secondDropDownMatch)
                                            adListCompare = AdListCompare.Approved;
                                    }

                                    break;
                                case FilterControlType.DropDown:

                                    //Check so the first dropdown value compare
                                    //If the index is the first then any value will do
                                    if (seartchFilterValue.FilterIndexPosition1 == FilterIndexPosition.First)
                                    {
                                        if (adsFilterValues.ValueNumber.Value <= seartchFilterValue.AdsFilterValues1.ValueNumber.Value)
                                            firstDropDownMatch = true;
                                    }
                                    if (seartchFilterValue.FilterIndexPosition1 == FilterIndexPosition.Last)
                                    {
                                        if (adsFilterValues.ValueNumber.Value >= seartchFilterValue.AdsFilterValues1.ValueNumber.Value)
                                            firstDropDownMatch = true;
                                    }
                                    else
                                    {
                                        if (adsFilterValues.ValueNumber.Value == seartchFilterValue.AdsFilterValues1.ValueNumber.Value)
                                            firstDropDownMatch = true;
                                    }

                                    if (firstDropDownMatch)
                                        adListCompare = AdListCompare.Approved;

                                    break;
                                case FilterControlType.TextBox:
                                    if (adsFilterValues.ValueString.Equals(seartchFilterValue.AdsFilterValues1.ValueString))
                                        adListCompare = AdListCompare.Approved;
                                    break;
                                case FilterControlType.CheckBox:
                                    if (adsFilterValues.ValueNumber != null && adsFilterValues.ValueNumber.Value == seartchFilterValue.AdsFilterValues1.ValueNumber.Value)
                                        adListCompare = AdListCompare.Approved;
                                    break;
                                default:
                                    adListCompare = AdListCompare.NotCompered;
                                    break;
                            }

                            //If no value is set, then break;
                            if (adListCompare != AdListCompare.Approved)
                                break;

                            machedFilterCount++;
                        }
                    }
                    else
                    {
                        //If the ad is missing the filter then return it anyway, it might as well be correct
                        adListCompare = AdListCompare.Approved;
                        machedFilterCount = adCategoryFilterList.Count();
                    }
                }
            }
            else
            {
                adListCompare = AdListCompare.Approved;
                machedFilterCount = adCategoryFilterList.Count();
            }


            if (adListCompare == AdListCompare.Approved && machedFilterCount == adCategoryFilterList.Count())
                tmpAdList2.Add(ad);
        }
        #endregion

        if (adList.ALS.OB == (int)AdListOrderBy.Price)
            tmpAdList2 = tmpAdList2.OrderBy(c => c.Price).ToList();


        totalAds = tmpAdList2.Count();

        return tmpAdList2.Skip((adList.ALS.P - 1) * adList.ALS.CP).Take(adList.ALS.CP).ToList();
    }
}

编辑 2：更新

主 GetAd 方法：

public List<Ad> GetAds(AdList adList, DateTime fetchAdsTo, out int totalAds)
        {
            LocationModel locationModel = new LocationModel();
            FilterModel filterModel = new FilterModel();

            List<AdCategoryFilter> adCategoryFilterList;
            List<AdsFilterValueWrapper> seartchFilterValueList;

            int categoryId = -1;
            List<Ad> outputList;

            totalAds = 0;

            #region Fetch the first ads by location
            outputList = GetAdsByLocations(locationModel.GetLocationOrderList(adList.GetLocationIds()), fetchAdsTo, false);
            if(outputList.Count < 1)
                return outputList;
            #endregion

            #region GetFilters
            categoryId = AdHandler.Instance.ExtractCategoryId(adList.CS);
            adCategoryFilterList = filterModel.GetCategoryFilterByCategory(categoryId);
            seartchFilterValueList = FilterHandler.Instance.ConvertAdFilterToModel(adList.F, adCategoryFilterList, FilterType.Display);
            #endregion

            #region Filter Default filters (Buy, Let, Sell, Swap, WishRent)
            FilterDefaultCustomFilters(outputList, adCategoryFilterList, seartchFilterValueList);
            if (outputList.Count == 0)
                return outputList;
            else
            {
                #region Remove default filters fom filterList
                adCategoryFilterList = adCategoryFilterList.Where(c => ((PublicAdFilterKey)c.PublicAdFilterKey) != PublicAdFilterKey.Buy &&
                                                ((PublicAdFilterKey)c.PublicAdFilterKey) != PublicAdFilterKey.Let &&
                                                ((PublicAdFilterKey)c.PublicAdFilterKey) != PublicAdFilterKey.Sell &&
                                                ((PublicAdFilterKey)c.PublicAdFilterKey) != PublicAdFilterKey.Swap &&
                                                ((PublicAdFilterKey)c.PublicAdFilterKey) != PublicAdFilterKey.WishRent).ToList();
                #endregion
            }
            #endregion

            #region Filter Custom filters
            this.FilterCustomFilters(outputList, adCategoryFilterList, seartchFilterValueList);
            #endregion

            #region Order
            switch ((AdListOrderBy)adList.ALS.OB)
            {
                case AdListOrderBy.Price:
                    outputList = outputList.OrderBy(c => c.Price).ToList(); break;
                case AdListOrderBy.Latest:
                    outputList = outputList.OrderByDescending(c => c.PublishedDate).ToList(); break;
            }
            #endregion

            #region Total Ad Count
            totalAds = outputList.Count();
            #endregion

            #region Paging
            outputList = outputList.Skip((adList.ALS.P - 1) * adList.ALS.CP).Take(adList.ALS.CP).ToList();
            #endregion

            return outputList;
        }

GetAdByLocation strong>

public List<Ad> GetAdsByLocations(string[] locationLevelOrderList, DateTime? fetchAdsTo, Boolean inactive) //, List<Ad> adList = null)
{
    List<Ad> output;

    using (BissEntities context = new BissEntities())
    {
        if (fetchAdsTo.HasValue)
        {
            if (locationLevelOrderList.Count() == 0)
            {
                output = (from a in context.Ads
                            join l in context.Location on a.UserLocationId equals l.Id
                            where a.InactivatedDate.HasValue == inactive &&
                            (a.PublishedDate.HasValue && a.PublishedDate.Value.CompareTo(fetchAdsTo.Value) >= 1)
                            select a).ToList();
            }
            else
            {
                output = (from a in context.Ads
                            join l in context.Location on a.UserLocationId equals l.Id
                            where a.InactivatedDate.HasValue == inactive &&
                            (a.PublishedDate.HasValue && a.PublishedDate.Value.CompareTo(fetchAdsTo.Value) >= 1) &&
                            (locationLevelOrderList.Where(c => l.LevelOrder.StartsWith(c)).FirstOrDefault() != null) 
                            select a).ToList();
            }

        }
        else
        {
            if (locationLevelOrderList.Count() == 0)
            {
                output = (from a in context.Ads
                            join l in context.Location on a.UserLocationId equals l.Id
                            where a.InactivatedDate.HasValue == inactive
                            select a).ToList();
            }
            else
            {
                output = (from a in context.Ads
                            join l in context.Location on a.UserLocationId equals l.Id
                            where a.InactivatedDate.HasValue == inactive &&
                            (locationLevelOrderList.Count() == 0 || locationLevelOrderList.Where(c => l.LevelOrder.StartsWith(c)).FirstOrDefault() != null)
                            select a).ToList();
            }
        }
    }

    return output;
}

注意： 主 GetAd 中名称以 Filter 开头的方法仅适用于集合（无数据库操作）

Answer 1

在您的查询中，您可以进行比较：

 ... locationIdList != null ...

由于 locationIdList 的类型为 int[]，因此无法翻译查询，因为它仅支持简单比较（如错误所述） 。

您应该在查询之外而不是在查询内执行这些检查。但是，由于它们是在方法内初始化的，因此您应该确保它们已初始化并省略检查，因为这是不必要的。

---

我强烈建议重构整个方法和查询。这是非常长且难以理解的。将代码块移动到单独的方法中，执行您需要的一小部分，然后将它们全部放在一起。它将使您的代码更容易维护，并且更容易纠正此类错误。

Answer 2

最后一个示例适用于 Entity Framework 4。如果出现异常，您的应用程序很可能是使用不支持 Contains 的第一个版本的 Entity Framework 构建的 .NET 3.5。