.net Odata$expand在动态模型创建中不起作用

我参考了美国的经验，完成了动态edm模型的创建

我已将odata查询选项添加到上述项目中$过滤器、$top、$count、$select（不展开）正在成功运行。但是当我查询

~/odata/Products？$expand=DetailInfo

时，它不会返回DetailInfo的任何值。有人能帮我解决这个问题吗

 EdmEntityObject entity = new EdmEntityObject(entityType);
 entity.TrySetPropertyValue("Name", "abc");
 entity.TrySetPropertyValue("ID", 1);
 entity.TrySetPropertyValue("DetailInfo", CreateDetailInfo(88,"abc_detailinfo", entity.ActualEdmType)); 
 collection.Add(entity);
 entity = new EdmEntityObject(entityType);
 entity.TrySetPropertyValue("Name", "def");
 entity.TrySetPropertyValue("ID", 2);
 entity.TrySetPropertyValue("DetailInfo", CreateDetailInfo(99, "def_detailinfo", entity.ActualEdmType));
 collection.Add(entity);

执行上述代码后，集合保存2个值，每个值有3个属性、2个结构属性（名称、id）和1个导航属性，其中包含DetailInfo的值

当前输出：

[{“Name”：“abc”，“ID”：1}，{“Name”：“def”，“ID”：2}]}

预期输出：

[{"Name":"abc","ID":1, "DetailInfo":{"ID":88,"Title":"abc_detailinfo"}},{"Name":"def","ID":2, "DetailInfo":{"ID":99,"Title":"def_detailinfo"}}]}

---

在使用动态EDM模型创建时，您必须自己实现应用ODataQueryOptions的逻辑

这意味着您的控制器中的GET（id）方法如下所示

    public IEdmEntityObject Get(string key)
    {
        // Get entity type from path.
        ODataPath path = Request.ODataFeature().Path;
        IEdmEntityType entityType = (IEdmEntityType)path.EdmType;

        // Create an untyped entity object with the entity type.
        EdmEntityObject entity = new EdmEntityObject(entityType);

        string sourceString = Request.GetDataSource();
        DataSourceProvider.Get(sourceString, key, entity);


        IEdmModel model = Request.GetModel();
        ODataQueryContext queryContext = new ODataQueryContext(model, entityType, path);
        ODataQueryOptions queryOptions = new ODataQueryOptions(queryContext, Request);

        // Apply query options here.

        return entity;
    }

    public EdmEntityObjectCollection Get()
    {
        // Get entity set's EDM type: A collection type.
        ODataPath path = Request.ODataFeature().Path;
        IEdmCollectionType collectionType = (IEdmCollectionType)path.EdmType;
        IEdmEntityTypeReference entityType = collectionType.ElementType.AsEntity();

        // Create an untyped collection with the EDM collection type.
        EdmEntityObjectCollection collection =
            new EdmEntityObjectCollection(new EdmCollectionTypeReference(collectionType));

        string sourceString = Request.GetDataSource();
        // Add untyped objects to collection.
        DataSourceProvider.Get(sourceString, entityType, collection);


        IEdmModel model = Request.GetModel();
        ODataQueryContext queryContext = new ODataQueryContext(model, collectionType.AsElementType(), path);
        ODataQueryOptions queryOptions = new ODataQueryOptions(queryContext, Request);

        // Apply query options here.

        return collection;
    }

这意味着您的控制器中的GET方法如下所示

    public IEdmEntityObject Get(string key)
    {
        // Get entity type from path.
        ODataPath path = Request.ODataFeature().Path;
        IEdmEntityType entityType = (IEdmEntityType)path.EdmType;

        // Create an untyped entity object with the entity type.
        EdmEntityObject entity = new EdmEntityObject(entityType);

        string sourceString = Request.GetDataSource();
        DataSourceProvider.Get(sourceString, key, entity);


        IEdmModel model = Request.GetModel();
        ODataQueryContext queryContext = new ODataQueryContext(model, entityType, path);
        ODataQueryOptions queryOptions = new ODataQueryOptions(queryContext, Request);

        // Apply query options here.

        return entity;
    }

    public EdmEntityObjectCollection Get()
    {
        // Get entity set's EDM type: A collection type.
        ODataPath path = Request.ODataFeature().Path;
        IEdmCollectionType collectionType = (IEdmCollectionType)path.EdmType;
        IEdmEntityTypeReference entityType = collectionType.ElementType.AsEntity();

        // Create an untyped collection with the EDM collection type.
        EdmEntityObjectCollection collection =
            new EdmEntityObjectCollection(new EdmCollectionTypeReference(collectionType));

        string sourceString = Request.GetDataSource();
        // Add untyped objects to collection.
        DataSourceProvider.Get(sourceString, entityType, collection);


        IEdmModel model = Request.GetModel();
        ODataQueryContext queryContext = new ODataQueryContext(model, collectionType.AsElementType(), path);
        ODataQueryOptions queryOptions = new ODataQueryOptions(queryContext, Request);

        // Apply query options here.

        return collection;
    }