Breezejs SaveChanges：是否可以以某种方式返回自定义的SaveResult对象？ [英] Breezejs SaveChanges: is it possible to return a custom SaveResult object, somehow?

问题描述

说我有一个电影实体，平均得分。用户可以对电影进行评分，为此我在客户端上调用datacontext.savechanges，将评分对象发送到服务器。在服务器上，调用SaveChanges方法，然后在BeforeSaveEntity方法中，调整电影的平均得分。

Say I have a movie entity, with an average score. A user can rate a movie, and for that I call datacontext.savechanges on the client, sending a Rating object to the server. On the server, the SaveChanges method is called, and in the BeforeSaveEntity method, I adapt the movie's average score.

这里的问题是：如何从服务器的SaveChanges方法，例如在SaveResult对象内部？

Here's the question: how to return that average score from the server's SaveChanges method, for example inside the SaveResult object?

我以为可以将电影实体添加到SaveResult Entities列表中，但是：
-我会需要从saveBundle参数
中访问属性-我将不得不重新查询数据库，就像我在BeforeSaveEntity

I thought I could add the movie entity to the SaveResult Entities list, but then: - I would need to access attributes from within the saveBundle parameter - I would have to requery the DB, which I just did in BeforeSaveEntity

谢谢

尼古拉斯

推荐答案

是的，有可能。

像平常一样将控制器写成EDMX。对于我们来说，它翻译成这样的东西：

Write your controller against an EDMX as you would do normally do. For us, it translates into something like this:

public class PersonalizationController : MultiTenantBreezeController<PersonalizationEntities>

其中PersonalizationEntities是ObjectContext。

where the PersonalizationEntities is an ObjectContext.

然后在服务器上，我们只需定义SaveChanges（不要介意重写，我们有一个基类）

Then on the server, we simply define the SaveChanges (do not mind the override, we do have a base class)

[HttpPost]
public override SaveResult SaveChanges(JObject saveBundle)
{
     // Deserialize the object that needs to get saved (ApplicationDefaults is my DTO)
     var applicationDefaultsList = JsonConvert.DeserializeObject<List<ApplicationDefaults>>(saveBundle.SelectToken("entities").ToString());

     // Do whatever logic you need to save the data
     using (var repo = ServiceLocator.Current.Container.Resolve<IUserPreferenceRepository>())
     {
          // Your save logic here
     }

     // Construct the save result to inform the client that the server has completed the save operation
     var keyMappings = new List<KeyMapping>();
     return new SaveResult()
     {
         Entities = applicationDefaultsList.Cast<object>().ToList(),
         Errors = null,
         KeyMappings = keyMappings
     };
}

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