C# net core Odata web api json格式异常

Question

我想从 C# net 5 web api 返回一个包含复杂对象集合的实体（“Question5Point1”）。 我的问题是，我的 json 结果在复杂对象的开头被剪切。 它看起来像这样：

我的元数据如下所示：

我的代码是这样的：

结果是：

每个字段/属性都已填写。 为什么会发生此错误，我该怎么办？ 在调试的输出中，我看到了这个异常：

    Microsoft.OData.ODataException: An internal error 'EdmLibraryExtensions_ToTypeReference' occurred.
   at Microsoft.OData.Metadata.EdmLibraryExtensions.ToTypeReference(IEdmType type, Boolean nullable)
   at Microsoft.OData.Metadata.EdmLibraryExtensions.ToTypeReference(IEdmType type)
   at Microsoft.OData.TypeNameOracle.ResolveAndValidateTypeFromTypeName(IEdmModel model, IEdmStructuredType expectedType, String typeName, IWriterValidator writerValidator)
   at Microsoft.OData.ODataWriterCore.GetResourceType(ODataResourceBase resource)
   at Microsoft.OData.ODataWriterCore.ValidateResourceForResourceSet(ODataResourceBase resource, ResourceBaseScope resourceScope)
   at Microsoft.OData.ODataWriterCore.<>c__DisplayClass121_0.<WriteStartResourceImplementation>b__0()
   at Microsoft.OData.ODataWriterCore.InterceptException(Action action)
   at Microsoft.OData.ODataWriterCore.WriteStartResourceImplementation(ODataResource resource)
   at Microsoft.OData.ODataWriterCore.<>c__DisplayClass49_0.<WriteStartAsync>b__0()
   at Microsoft.OData.TaskUtils.GetTaskForSynchronousOperation(Action synchronousOperation)
--- End of stack trace from previous location ---
   at Microsoft.AspNet.OData.Formatter.Serialization.ODataResourceSerializer.WriteResourceAsync(Object graph, ODataWriter writer, ODataSerializerContext writeContext, IEdmTypeReference expectedType)
   at Microsoft.AspNet.OData.Formatter.Serialization.ODataResourceSetSerializer.WriteResourceSetAsync(IEnumerable enumerable, IEdmTypeReference resourceSetType, ODataWriter writer, ODataSerializerContext writeContext)
   at Microsoft.AspNet.OData.Formatter.Serialization.ODataResourceSerializer.WriteComplexAndExpandedNavigationPropertyAsync(IEdmProperty edmProperty, SelectItem selectItem, ResourceContext resourceContext, ODataWriter writer)
   at Microsoft.AspNet.OData.Formatter.Serialization.ODataResourceSerializer.WriteComplexPropertiesAsync(SelectExpandNode selectExpandNode, ResourceContext resourceContext, ODataWriter writer)
   at Microsoft.AspNet.OData.Formatter.Serialization.ODataResourceSerializer.WriteResourceAsync(Object graph, ODataWriter writer, ODataSerializerContext writeContext, IEdmTypeReference expectedType)
   at Microsoft.AspNet.OData.Formatter.Serialization.ODataResourceSerializer.WriteObjectAsync(Object graph, Type type, ODataMessageWriter messageWriter, ODataSerializerContext writeContext)
   at Microsoft.AspNet.OData.Formatter.ODataOutputFormatterHelper.WriteToStreamAsync(Type type, Object value, IEdmModel model, ODataVersion version, Uri baseAddress, MediaTypeHeaderValue contentType, IWebApiUrlHelper internaUrlHelper, IWebApiRequestMessage internalRequest, IWebApiHeaders internalRequestHeaders, Func`2 getODataMessageWrapper, Func`2 getEdmTypeSerializer, Func`2 getODataPayloadSerializer, Func`1 getODataSerializerContext)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeNextResultFilterAsync>g__Awaited|29_0[TFilter,TFilterAsync](ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResultExecutedContextSealed context)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.ResultNext[TFilter,TFilterAsync](State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeResultFilters()
--- End of stack trace from previous location ---
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeFilterPipelineAsync>g__Awaited|19_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)
   at Microsoft.AspNetCore.Builder.RouterMiddleware.Invoke(HttpContext httpContext)
   at Microsoft.AspNet.OData.Batch.ODataBatchMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Server.IIS.Core.IISHttpContextOfT`1.ProcessRequestAsync()

Answer 1

我在导航属性列表中遇到了同样的问题，请确保您的 Key(s) 是唯一的，我在 Key 中有 null，因此 json 已被剪切。

Answer 2

当我有两个 OData 控制器返回两个不同的数据类型时发生了这个错误，这些数据类型包含一个具有相同名称的内部类：

public class OEntity
{
    [Key]
    public int Id { get; set; }
    public string Name { get; set; }
    ...
    public Day[] Days { get; set; }

    // Daily information related to this entity
    public class Day
    {
        public DateTime Date { get; set; }
        public double Deposit { get; set; }
        ...
    }
}

public class OCost
{
    [Key]
    public int Id { get; set; }
    public double TotalCost { get; set; }
    public string Currency { get; set; }
    ...
    public Day[] Days { get; set; }

    // Causes "internal error 'EdmLibraryExtensions_ToTypeReference'" 
    // in the OEntity controller. Must rename!
    public class Day
    {
        public DateTime Date { get; set; }
        public double Cost { get; set; }
    }
}

所以请确保您的所有数据类都没有相同的名称。