ExplicitExpansion() 导致 OData 扩展不起作用答案

【问题标题】：ExplicitExpansion() cause OData expand not workExplicitExpansion() 导致 OData 扩展不起作用
【发布时间】：2020-08-20 09:13:43
【问题描述】：

使用 ExplicitExpansion() 时，Odata 扩展不起作用。我的 DTo 和 EF 模型可以在下面的链接中找到。 Querying DTOs based on EF using Odata

我的 Automapper 类：

public class AutoMapperProfile : Profile
{
    public AutoMapperProfile()
    {
        CreateMap<ClientRef, ClientContract>().
        ForMember(dest => dest.ValidFrom,
        opt =>
        {
            opt.MapFrom(y => y.Clients.FirstOrDefault(x => x.ValidFrom <= DateTime.Now && x.ValidTo > DateTime.Now).ValidFrom);
        }).
        ForMember(dest => dest.ValidTo,
        opt =>
        {
            opt.MapFrom(y => y.Clients.FirstOrDefault(x => x.ValidFrom <= DateTime.Now && x.ValidTo > DateTime.Now).ValidTo);
        }).
       ForMember(dest => dest.FirstName,
        opt =>
        {
            opt.MapFrom(y => y.PhysicalPeople.FirstOrDefault(x => x.ValidFrom <= DateTime.Now && x.ValidTo > DateTime.Now).FirstName);
        }).
        ForMember(dest => dest.LastName,
        opt =>
        {
            opt.MapFrom(y => y.PhysicalPeople.FirstOrDefault(x => x.ValidFrom <= DateTime.Now && x.ValidTo > DateTime.Now).LastName);
        }).
        ForMember(dest => dest.BirthDate,
        opt =>
        {
            opt.MapFrom(y => y.PhysicalPeople.FirstOrDefault(x => x.ValidFrom <= DateTime.Now && x.ValidTo > DateTime.Now).BirthDate);
        }).
        ForMember(dest => dest.FatherName,
        opt =>
        {
            opt.MapFrom(y => y.PhysicalPeople.FirstOrDefault(x => x.ValidFrom <= DateTime.Now && x.ValidTo > DateTime.Now).FatherName);
        }).
        ForMember(dest => dest.CompanyName,
        opt =>
        {
            opt.MapFrom(y => y.Companies.FirstOrDefault(x => x.ValidFrom <= DateTime.Now && x.ValidTo > DateTime.Now).CompanyName);

        })
        .
        ForMember(dest => dest.PinNumber,
        opt =>
        {
            opt.MapFrom(y => y.PhysicalPeople.FirstOrDefault(x => x.ValidFrom <= DateTime.Now && x.ValidTo > DateTime.Now).Pin);

        }).
        ForMember(dest => dest.Position,
        opt =>
        {
            opt.MapFrom(y => y.PhysicalPeople.FirstOrDefault(x => x.ValidFrom <= DateTime.Now && x.ValidTo > DateTime.Now).Position);

        }).
        ForMember(dest => dest.PositionCustom,
        opt =>
        {
            opt.MapFrom(y => y.PhysicalPeople.FirstOrDefault(x => x.ValidFrom <= DateTime.Now && x.ValidTo > DateTime.Now).PositionCustom);

        }).
        ForMember(dest => dest.ClientType,
        opt =>
        {
            opt.MapFrom(y => y.Clients.FirstOrDefault(x => x.ValidFrom <= DateTime.Now && x.ValidTo > DateTime.Now).ClientType);

        })
        .
        ForMember(dest => dest.Documents,
        opt =>
        {
            opt.MapFrom(y => y.Documents.Where(x => x.ValidFrom <= DateTime.Now && x.ValidTo > DateTime.Now));
            //opt.ExplicitExpansion();
        })
        .ForMember(dest => dest.ContactsInfo,
        opt =>
        {
            opt.MapFrom(y => y.ClientContactInfoComps.Where(x => x.ValidFrom <= DateTime.Now && x.ValidTo > DateTime.Now).Select(x => x.ContactInfo));
            //opt.ExplicitExpansion();
        }).
        ForMember(dest => dest.ClientComment,
        opt =>
        {
            opt.MapFrom(y => y.CommentComps.Where(x => x.Contact == null).Select(x => x.Comment));
            //opt.ExplicitExpansion();
        }).
        ForMember(dest => dest.Relations,
        opt =>
        {
            opt.MapFrom(y => y.ClientRelationCompClient1Navigations);
            //opt.ExplicitExpansion();
        })
        ;


        CreateMap<Document, DocumentContract>();

        CreateMap<ContactInfo, ContactInfoContract>().
        ForMember(dest => dest.ContactComments,
        opt =>
        {
        opt.MapFrom(y => y.CommentComps.Select(x => x.Comment));
        });

        CreateMap<ClientRelationComp, RelationContract>().
            ForMember(dest => dest.ClientINN,
            opt => {
                opt.MapFrom(x => x.Client2);
            }).
            ForMember(dest => dest.RelationType,
            opt => {
                opt.MapFrom(x => x.RelationId);
            });

        CreateMap<ICollection<Client>, ClientContract>();
        CreateMap<ICollection<PhysicalPerson>, ClientContract>();
        CreateMap<ICollection<Company>, ClientContract>();
        CreateMap<Comment, CommentContract>();
        CreateMap<ICollection<Comment>, ICollection<ContactInfoContract>>();
        CreateMap<ICollection<ClientRelationComp>, ClientRef>();
        
    }
}

我的控制器：

public class ClientContractController : ODataController
{
    CRMContext _context;
    IMapper _mapper;
    public ClientContractController(CRMContext ctx, IMapper mapper )
    {
        _context = ctx;
        _mapper = mapper;
    }

    [EnableQuery(MaxExpansionDepth = 10)]
    public IQueryable<ClientContract> Get()
    {
        return _mapper.ProjectTo<ClientContract>(_context.ClientRefs).Where(x => x.ValidFrom <= DateTime.Now && x.ValidTo >= DateTime.Now);
    }
}

这给出了以下异常 https://localhost:44371/odata/clientcontract?$expand=relations

System.InvalidOperationException：无法翻译 LINQ 表达式“$it”。以可翻译的形式重写查询，或通过插入对 AsEnumerable()、AsAsyncEnumerable()、ToList() 或 ToListAsync() 的调用显式切换到客户端评估。有关更多信息，请参阅https://go.microsoft.com/fwlink/?linkid=2101038。在 Microsoft.EntityFrameworkCore.Query.Internal.RelationalProjectionBindingExpressionVisitor.Visit（表达式表达式）在 Microsoft.EntityFrameworkCore.Query.Internal.RelationalProjectionBindingExpressionVisitor.VisitMemberAssignment(MemberAssignment memberAssignment) 在 System.Linq.Expressions.ExpressionVisitor.VisitMemberBinding（MemberBinding 节点）在 Microsoft.EntityFrameworkCore.Query.Internal.RelationalProjectionBindingExpressionVisitor.VisitMemberInit（MemberInitExpression memberInitExpression）在 System.Linq.Expressions.MemberInitExpression.Accept（ExpressionVisitor 访问者）在 System.Linq.Expressions.ExpressionVisitor.Visit（表达式节点）在 Microsoft.EntityFrameworkCore.Query.Internal.RelationalProjectionBindingExpressionVisitor.Visit（表达式表达式）在 System.Linq.Expressions.ExpressionVisitor.VisitLambda[T](Expression1 node) at System.Linq.Expressions.Expression1.Accept(ExpressionVisitor 访问者) 在 System.Linq.Expressions.ExpressionVisitor.Visit（表达式节点）在 Microsoft.EntityFrameworkCore.Query.Internal.RelationalProjectionBindingExpressionVisitor.Visit（表达式表达式）在 System.Dynamic.Utils.ExpressionVisitorUtils.VisitArguments（ExpressionVisitor 访问者，IArgumentProvider 节点）在 System.Linq.Expressions.ExpressionVisitor.VisitMethodCall（MethodCallExpression 节点）在 System.Linq.Expressions.MethodCallExpression.Accept（ExpressionVisitor 访问者）在 System.Linq.Expressions.ExpressionVisitor.Visit（表达式节点）在 Microsoft.EntityFrameworkCore.Query.Internal.RelationalProjectionBindingExpressionVisitor.Visit（表达式表达式）在 Microsoft.EntityFrameworkCore.Query.Internal.RelationalProjectionBindingExpressionVisitor.VisitMemberAssignment(MemberAssignment memberAssignment) 在 System.Linq.Expressions.ExpressionVisitor.VisitMemberBinding（MemberBinding 节点）在 Microsoft.EntityFrameworkCore.Query.Internal.RelationalProjectionBindingExpressionVisitor.VisitMemberInit（MemberInitExpression memberInitExpression）在 System.Linq.Expressions.MemberInitExpression.Accept（ExpressionVisitor 访问者）在 System.Linq.Expressions.ExpressionVisitor.Visit（表达式节点）在 Microsoft.EntityFrameworkCore.Query.Internal.RelationalProjectionBindingExpressionVisitor.Visit（表达式表达式）在 Microsoft.EntityFrameworkCore.Query.Internal.RelationalProjectionBindingExpressionVisitor.VisitMemberAssignment(MemberAssignment memberAssignment) 在 System.Linq.Expressions.ExpressionVisitor.VisitMemberBinding（MemberBinding 节点）在 Microsoft.EntityFrameworkCore.Query.Internal.RelationalProjectionBindingExpressionVisitor.VisitMemberInit（MemberInitExpression memberInitExpression）在 System.Linq.Expressions.MemberInitExpression.Accept（ExpressionVisitor 访问者）在 System.Linq.Expressions.ExpressionVisitor.Visit（表达式节点）在 Microsoft.EntityFrameworkCore.Query.Internal.RelationalProjectionBindingExpressionVisitor.Visit（表达式表达式）在 Microsoft.EntityFrameworkCore.Query.Internal.RelationalProjectionBindingExpressionVisitor.Translate（SelectExpression 选择表达式，表达式表达式）在 Microsoft.EntityFrameworkCore.Query.RelationalQueryableMethodTranslatingExpressionVisitor.TranslateSelect（ShapedQueryExpression 源，LambdaExpression 选择器）在 Microsoft.EntityFrameworkCore.Query.QueryableMethodTranslatingExpressionVisitor.VisitMethodCall(MethodCallExpression methodCallExpression) 在 System.Linq.Expressions.MethodCallExpression.Accept（ExpressionVisitor 访问者）在 System.Linq.Expressions.ExpressionVisitor.Visit（表达式节点）在 Microsoft.EntityFrameworkCore.Query.QueryCompilationContext.CreateQueryExecutor[TResult]（表达式查询）在 Microsoft.EntityFrameworkCore.Storage.Database.CompileQuery[TResult]（表达式查询，布尔异步）在 Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.CompileQueryCore[TResult]（IDatabase 数据库，表达式查询，IModel 模型，布尔异步）在 Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.c__DisplayClass12_01.<ExecuteAsync>b__0() at Microsoft.EntityFrameworkCore.Query.Internal.CompiledQueryCache.GetOrAddQuery[TResult](Object cacheKey, Func1 编译器）在 Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.ExecuteAsync[TResult]（表达式查询，CancellationToken cancelToken）在 Microsoft.EntityFrameworkCore.Query.Internal.EntityQueryProvider.ExecuteAsync[TResult]（表达式表达式，CancellationToken cancelToken）在 Microsoft.EntityFrameworkCore.Query.Internal.EntityQueryable1.GetAsyncEnumerator(CancellationToken cancellationToken) at Microsoft.AspNetCore.Mvc.Infrastructure.AsyncEnumerableReader.ReadInternal[T](Object value) at Microsoft.AspNetCore.Mvc.Infrastructure.ObjectResultExecutor.ExecuteAsyncEnumerable(ActionContext context, ObjectResult result, Object asyncEnumerable, Func2 读者）在 Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Logged|21_0（ResourceInvoker 调用程序，IActionResult 结果）在 Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|29_0[TFilter,TFilterAsync]（ResourceInvoker 调用者，Task lastTask，State next，Scope 范围，Object state，Boolean isCompleted）在 Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow（ResultExecutedContextSealed 上下文）在 Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.ResultNext[TFilter,TFilterAsync](State& next, Scope& scope, Object& state, Boolean& isCompleted) 在 Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeResultFilters() --- 从先前抛出异常的位置结束堆栈跟踪 --- 在 Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|19_0（ResourceInvoker 调用程序，任务 lastTask，下一个状态，作用域范围，对象状态，布尔 isCompleted）在 Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Logged|17_1（ResourceInvoker 调用程序）在 Microsoft.AspNetCore.Routing.EndpointMiddleware.g__AwaitRequestTask|6_0（端点端点，任务 requestTask，ILogger 记录器）在 Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke（HttpContext 上下文）在 Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext 上下文)

【问题讨论】：

标签： asp.net-core odata automapper

【解决方案1】：

20202 年 8 月 21 日更新

没有explicit instructions，AutoMapper 将展开结果中的所有成员。

要控制在投影期间扩展哪些成员，请在配置中设置ExplicitExpansion，然后传入要显式扩展的成员：

dbContext.Orders.ProjectTo<OrderDto>(configuration,
    dest => dest.Customer,
    dest => dest.LineItems);
// or string-based
dbContext.Orders.ProjectTo<OrderDto>(configuration,
    null,
    "Customer",
    "LineItems");
// for collections
dbContext.Orders.ProjectTo<OrderDto>(configuration,
    null,
    dest => dest.LineItems.Select(item => item.Product));

使用OData时使用属性名称而不是属性名称。

OData 客户端库依赖于它自己的属性OriginalNameAttribute 在服务器发出类/成员名称时获取它们的知识。详情可以在here看到。

【讨论】：

没用。我删除了 DataContract/DataMember 。但是抛出异常
如果我删除 ExplicitExpansion() 它可以工作，但在 SQL 中生成了 2 个连接。但是如果我添加了 ExplicitExpansion 我会得到上面的异常。
也许你可以看看这个issue。你的也一样
这行得通，但我发现了其他问题，expand 会生成 2 个左连接到同一个表。
@user3315759，如果这个问题解决了，请mark it帮助更多的人。请检查我发布到您的左连接问题的答案。