BreezeJs导航属性计数 [英] BreezeJs Navigation Property Count

问题描述

我刚刚开始使用BreezeJS，并认为它很棒。它为我节省了很多后端管道代码，这就是为什么我首先对其进行调查的原因。我想做的一件事是显示一些帐户的列表及其联系方式。目前，我正在使用以下代码，联系人字段是EF6中的导航属性。这段代码的问题是，当我真正需要的只是计数时，我正在下载每个帐户（数千个）的所有联系人。理想情况下，我希望我的select语句是这样的'.select（'AccountID，AccountName，Contacts.Count（）'）'，但我不认为OData / BreezeJS支持这一点。大声考虑也许解决方案是创建另一个名为AccountsWithContactCounts之类的WebService方法并返回一个自定义类，但理想情况下，如果可以在breezejs客户端中执行此操作，我希望避免这种情况。

I've just started to use BreezeJS and think it is superb. It's saved me so much backend 'plumbing' code which was why I investigated it in the first place. One of the things I would like to be able to do is display a list of some accounts and a count of their contacts. At the moment I am using the code below, the Contacts field is a navigation property in EF6. The issue with this code is that I am downloading all of the contacts for each account (thousands of them) when really all I need is the count. Ideally I'd like my select statement to be something like this '.select('AccountID,AccountName, Contacts.Count()')' but I don't think OData/BreezeJS supports this. Thinking out loud maybe the solution is to create another WebService method called something like AccountsWithContactCounts and return a custom class but Ideally I'd like to avoid this if it is possible to do in the breezejs client.

如果这是一个基本问题，欢迎您提出任何想法和歉意。

Welcome any thoughts, apologies if this is a basic question.

breeze.EntityQuery.from('Accounts')
        .where(pred)
        .select('AccountID,AccountName, Contacts')
        .orderBy(orderbyClause(orderBy, orderByReverse))
        .skip(currentPage * pageItems)
        .take(pageItems)
        .noTracking()
        .using(breezemanager).execute()
        .then(function (response) {
            console.log(response.results.length + ' entities retrieved');
            $scope.items = response.results;
        })
        .catch(function (error) {
            console.log(error.message);
        })
        .finally(function () {
        });

我的微风服务看起来像这样：

And my breeze service looks like this:

  [HttpGet]
    public IQueryable<Account> Accounts()
    {
        return _contextProvider.Context.Accounts;
    }

推荐答案

正如Steve确认的答案是在Breeze控制器上创建新方法

As Steve confirmed the answer was to create a new method on the Breeze controller

 [HttpGet]
    public IQueryable<object> AccountsSummary()
    {
        return from t in _contextProvider.Context.Accounts
            select
                new
                {
                    t.AccountID,
                    t.AccountName,
                    ContactsCount = t.Contacts.Count()
                };
    }

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