实体框架6一对多关系System.Data.Entity.DynamicProxies

Question

在我们的EF 6代码优先应用程序中，在非跟踪情况下，我与一对多关系和导航属性存在问题。

public class User
{
    public int UserId { get; set; }

    public string Name { get; set; }

    public virtual List<File> Files { get; set; }
}

public class File
{
    public int FileId { get; set; }

    public string Number { get; set; }

    public int UserWhoCreatedId { get; set; }

    public User UserWhoCreated { get; set; }
}

我这样设置类型配置实体：

public class FileMap : EntityTypeConfiguration<File>
{
    public FileMap()
    {
        ToTable("File");

        HasKey(e => e.FileId);

        Property(e => e.Number).IsRequired().HasMaxLength(250);

        Property(e => e.UserWhoCreatedId).IsRequired();

        HasRequired(e => e.UserWhoCreated).WithMany(d => d.Files).HasForeignKey(x => x.UserWhoCreatedId);
    }
}

但是当我选择查看时，出现以下错误：

var query = Db.File.Include（x => x.UserWhoCreated）.AsNoTracking（）。OrderByDescending（x => x.FileId）.ToList（）;

{
    "Message": "Ocorreu um erro.",
    "ExceptionMessage": "O tipo 'ObjectContent`1' não pôde serializar o corpo da resposta para o tipo de conteúdo 'application/json; charset=utf-8'.",
    "ExceptionType": "System.InvalidOperationException",
    "StackTrace": null,
    "InnerException": {
        "Message": "Ocorreu um erro.",
        "ExceptionMessage": "Error getting value from 'Files' on 'System.Data.Entity.DynamicProxies.User_A02A99140F2593106849B9A48413541E1321CFF517D4E87EDBC0AADB1B1B5DC6'.",
        "ExceptionType": "Newtonsoft.Json.JsonSerializationException",
        "StackTrace": "   em Newtonsoft.Json.Serialization.DynamicValueProvider.GetValue(Object target)\r\n   em Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.CalculatePropertyValues(JsonWriter writer, Object value, JsonContainerContract contract, JsonProperty member, JsonProperty property, JsonContract& memberContract, Object& memberValue)\r\n   em Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeObject(JsonWriter writer, Object value, JsonObjectContract contract, JsonProperty member, JsonContainerContract collectionContract, JsonProperty containerProperty)\r\n   em Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue(JsonWriter writer, Object value, JsonContract valueContract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerProperty)\r\n   em Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeObject(JsonWriter writer, Object value, JsonObjectContract contract, JsonProperty member, JsonContainerContract collectionContract, JsonProperty containerProperty)\r\n   em Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue(JsonWriter writer, Object value, JsonContract valueContract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerProperty)\r\n   em Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeList(JsonWriter writer, IEnumerable values, JsonArrayContract contract, JsonProperty member, JsonContainerContract collectionContract, JsonProperty containerProperty)\r\n   em Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue(JsonWriter writer, Object value, JsonContract valueContract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerProperty)\r\n   em Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeObject(JsonWriter writer, Object value, JsonObjectContract contract, JsonProperty member, JsonContainerContract collectionContract, JsonProperty containerProperty)\r\n   em Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue(JsonWriter writer, Object value, JsonContract valueContract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerProperty)\r\n   em Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.Serialize(JsonWriter jsonWriter, Object value, Type objectType)\r\n   em Newtonsoft.Json.JsonSerializer.SerializeInternal(JsonWriter jsonWriter, Object value, Type objectType)\r\n   em System.Net.Http.Formatting.BaseJsonMediaTypeFormatter.WriteToStream(Type type, Object value, Stream writeStream, Encoding effectiveEncoding)\r\n   em System.Net.Http.Formatting.JsonMediaTypeFormatter.WriteToStream(Type type, Object value, Stream writeStream, Encoding effectiveEncoding)\r\n   em System.Net.Http.Formatting.BaseJsonMediaTypeFormatter.WriteToStream(Type type, Object value, Stream writeStream, HttpContent content)\r\n   em System.Net.Http.Formatting.BaseJsonMediaTypeFormatter.WriteToStreamAsync(Type type, Object value, Stream writeStream, HttpContent content, TransportContext transportContext, CancellationToken cancellationToken)\r\n--- Fim do rastreamento de pilha do local anterior onde a exceção foi gerada ---\r\n   em System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   em System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   em System.Web.Http.WebHost.HttpControllerHandler.<WriteBufferedResponseContentAsync>d__22.MoveNext()",
        "InnerException": {
            "Message": "Ocorreu um erro.",
            "ExceptionMessage": "When an object is returned with a NoTracking merge option, Load can only be called when the EntityCollection or EntityReference does not contain objects.",
            "ExceptionType": "System.InvalidOperationException",
            "StackTrace": "   em System.Data.Entity.Core.Objects.DataClasses.RelatedEnd.ValidateLoad[TEntity](MergeOption mergeOption, String relatedEndName, Boolean& hasResults)\r\n   em System.Data.Entity.Core.Objects.DataClasses.EntityCollection`1.Load(List`1 collection, MergeOption mergeOption)\r\n   em System.Data.Entity.Core.Objects.DataClasses.EntityCollection`1.Load(MergeOption mergeOption)\r\n   em System.Data.Entity.Core.Objects.DataClasses.RelatedEnd.DeferredLoad()\r\n   em System.Data.Entity.Core.Objects.Internal.LazyLoadBehavior.LoadProperty[TItem](TItem propertyValue, String relationshipName, String targetRoleName, Boolean mustBeNull, Object wrapperObject)\r\n   em System.Data.Entity.Core.Objects.Internal.LazyLoadBehavior.<>c__DisplayClass7`2.<GetInterceptorDelegate>b__1(TProxy proxy, TItem item)\r\n   em System.Data.Entity.DynamicProxies.User_A02A99140F2593106849B9A48413541E1321CFF517D4E87EDBC0AADB1B1B5DC6.get_Files()\r\n   em GetFiles(Object )\r\n   em Newtonsoft.Json.Serialization.DynamicValueProvider.GetValue(Object target)"
        }
    }
}