由于DTO映射，OdataController查询计划不是最佳的(OdataController query plan not optimal because of DTO mapping)

将DAL对象映射到DTO对象时，我得到一个意外的查询。

我有一些DAL对象：

public class MainDalObject { public Guid Id { get; set;} public string Description { get; set; } public ICollection<SubDalObject> Subs { get; set; } } public class SubDalObject { public Guid Id { get; set;} public string Description { get; set; } public MainDalObject Main { get; set; } }

我的DTO课程：

public class MainObject { public Guid Id { get; set;} public string Name { get; set; } public IEnumerable<SubObject> Subs { get; set; } } public class SubObject { public Guid Id { get; set;} public string Name { get; set; } public MainDalObject Main { get; set; } }

我的MainObject控制器包含一个IQueryable方法：

public IQueryable<MainObject> Get() { return (from m in Context.Get<MainDalObject>() select new MainObject { Id = m.Id, Name = m.Description, Subs = m.Subs.Select(s => new SubObject { Id = s.Id, Name = s.Name } }); }

这工作正常，但查询不是最佳的。当我在/ api / MainObject上触发查询时，我根本没有选择子项。但是当我查看查询时，无论如何它都在选择子项。

但是，当我将查询更改为/ api / MainObject？$ select = Id，Name时，查询未选择SubObjects。

所以我期待的是WebApi框架中的某个地方，当没有使用SelectExpandFilter时，响应编写器正在执行ToList（），而不指定Select语句。

我正在寻找解决这个问题的最佳位置，我可能会设置一个选择扩展ODataQueryOption，它可能会伪造一个选择或扩展调用，但我不确定这是否可行。

When mapping a DAL object to DTO object I get an unexpected query.

I have some DAL objects:

public class MainDalObject { public Guid Id { get; set;} public string Description { get; set; } public ICollection<SubDalObject> Subs { get; set; } } public class SubDalObject { public Guid Id { get; set;} public string Description { get; set; } public MainDalObject Main { get; set; } }

And my DTO classes:

public class MainObject { public Guid Id { get; set;} public string Name { get; set; } public IEnumerable<SubObject> Subs { get; set; } } public class SubObject { public Guid Id { get; set;} public string Name { get; set; } public MainDalObject Main { get; set; } }

My MainObject controller contains a IQueryable method:

public IQueryable<MainObject> Get() { return (from m in Context.Get<MainDalObject>() select new MainObject { Id = m.Id, Name = m.Description, Subs = m.Subs.Select(s => new SubObject { Id = s.Id, Name = s.Name } }); }

This works fine, however the query is not optimal. When i trigger the query on /api/MainObject , I am not selecting the subitems at all. But when i look at the query it is selecting the subItems anyway.

However when I change the query to /api/MainObject?$select=Id,Name , the query is not selecting the SubObjects.

So what I am expecting is that somewhere in the WebApi framework, when no SelectExpandFilter is used, the responsewriter is doing a ToList(), without specifying the Select statement.

I am looking for the best place to fix this problem, I could probably set a select expand ODataQueryOption that could fake an select or expand call, but I am not sure if that is the way to go.

最满意答案

如果其他人遇到此问题，这就是我为解决这个问题所做的工作。 select扩展查询应该从请求上下文中的edmmodel派生，但这基本上是它的工作原理。

public virtual IQueryable<TDTO> Get(ODataQueryOptions queryOptions) { if (queryOptions.SelectExpand == null) { var selectOption = new SelectExpandQueryOption("Id,Name", string.Empty, queryOptions.Context); Request.SetSelectExpandClause(selectOption.SelectExpandClause); } return (from m in Context.Get<MainDalObject>() select new MainObject { Id = m.Id, Name = m.Description, Subs = m.Subs.Select(s => new SubObject { Id = s.Id, Name = s.Name } }); }

If someone else runs in this problem, this is what I have done to fix it. The select expand query should be derived from the edmmodel in the request context, but this is basically how it works.

public virtual IQueryable<TDTO> Get(ODataQueryOptions queryOptions) { if (queryOptions.SelectExpand == null) { var selectOption = new SelectExpandQueryOption("Id,Name", string.Empty, queryOptions.Context); Request.SetSelectExpandClause(selectOption.SelectExpandClause); } return (from m in Context.Get<MainDalObject>() select new MainObject { Id = m.Id, Name = m.Description, Subs = m.Subs.Select(s => new SubObject { Id = s.Id, Name = s.Name } }); }

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