Question

如果我有Company个对象：

var companies = db.Companies.Where(...);

还有与User对象Company相关的one-to-many对象：

var users = db.Users.Where(...);

我如何达到select * from users where user.company in (company)这样的标准

从一些文章中读过，我尝试过类似的内容：

users.Where(x => companies.Contains(x.company))

但是似乎不起作用。我在这里错过了什么？

编辑

确切答案：

public PartialViewResult IndexGrid(String search)
{
    var companies = db.Users.Find(User.Identity.GetUserId()).Companies.AsQueryable();
    Guid[] guids = companies.Select(c => c.Id).ToArray();

    if (String.IsNullOrEmpty(search))
        return PartialView("_IndexGrid", db.Set<Quotation>().OrderByDescending(x => x.Code).AsQueryable()
            .Where(x => guids.Contains(x.Company.Id)));
    else
        return PartialView("_IndexGrid", db.Set<Quotation>().OrderByDescending(x => x.Code).AsQueryable()
            .Where(x => guids.Contains(x.Company.Id))
            .Where(x => x.Code.Contains(search)|| x.MasterCustomer.Name.Contains(search)));
}

Answer 1

将最后一个变体用作

users.Where(x => companies.Contains(x.company))

.Net不知道如何比较公司，并且使用引用来引用相等的对象。如果您的公司具有ID财产，请尝试此操作。如果没有，请告诉我。

users.Where(x => companies.Select(c => c.Id).Contains(x.company.Id))

Answer 2

我想您需要选择其ID：

var companies = db.Companies.Where(...);
var myUsers = db.Users.Where(w=>companies.Select(x=>x.Id).Contains(w.CompanyId)).ToList();

如果两者之间都有参考，则可以例如：

var myUsers = db.Users.Include(x=>x.Company)
                   .Where(w=>w.Company != null && w.Company.Name == "MyCompanyName")
                   .ToList();

WHERE IN子句AS对象实体框架

2 个答案: