EF核心2.2到EF核心3.1

Question

当我使用EF 2.2时，它运行此代码时没有任何问题：

var resource = locResRepo.GetWhere(i => i.ForApplication.ToLower() == applicationName.ToLower())
            .Where(resourcesConditionExpression)
            .Select(item => new ResourceKeyObject
            {
                Id = item.Id,
                ResourceKey = item.ResourceKey,
                ResourceKeyValues = item.ActualLocalizationTranslation
                .Where(translationConditionExpression)
                .Select(v => new ResourceKeyValues
                {
                    Language = v.Language,
                    KeyValue = v.Value

                }).ToList()
            }).ToList();

但是现在它抛出了错误：

System.InvalidOperationException: Processing of the LINQ expression '(MaterializeCollectionNavigation(
    navigation: Navigation: LocalizationResources.ActualLocalizationTranslation,
    subquery: (NavigationExpansionExpression
        Source: DbSet<ActualLocalizationTranslation>
            .Where(a => EF.Property<Nullable<int>>(l, "Id") != null && EF.Property<Nullable<int>>(l, "Id") == EF.Property<Nullable<int>>(a, "ResourceId"))
        PendingSelector: a => (NavigationTreeExpression
            Value: (EntityReference: ActualLocalizationTranslation)
            Expression: a)
    )
        .Where(i => EF.Property<Nullable<int>>((NavigationTreeExpression
            Value: (EntityReference: LocalizationResources)
            Expression: l), "Id") != null && EF.Property<Nullable<int>>((NavigationTreeExpression
            Value: (EntityReference: LocalizationResources)
            Expression: l), "Id") == EF.Property<Nullable<int>>(i, "ResourceId")))
    .Where(t => True)' by 'NavigationExpandingExpressionVisitor' failed. This may indicate either a bug or a limitation in EF Core. See https://go.microsoft.com/fwlink/?linkid=2101433 for more detailed information.
   at Microsoft.EntityFrameworkCore.Query.Internal.NavigationExpandingExpressionVisitor.VisitMethodCall(MethodCallExpression methodCallExpression)
   at System.Linq.Expressions.MethodCallExpression.Accept(ExpressionVisitor visitor) and so on.....

我真的不明白为什么..也许我知道一些东西，但我不知道如何实现它

Answer 1

从3.0开始，不再在客户端评估EF Core LINQ查询。learn more: MSDN

实际上，如果i.ForApplication属性做了一些计算，我认为你的问题可能出在它身上。

Answer 2

我找到了一个解决方案。之前的select必须是.ToList()，因为EF3.1逻辑