c# - 如何在外键项中获得计数？

Question

我需要得到所有bank的地方BankBranches cityId = filter.CityId > 0

代码：

 banks = from bank in banks
            where bank.BankBranches.Where(y => y.CityId == filter.CityId).Count() > 0
            select bank;
    var list = banks.ToList();

错误：

对于类型“System.Linq.IQueryable”[Model.Entities.BankBranch]，不允许从“Model.Entities.BankBranch”访问成员“Int32 CityId”。

Answer 1

 banks = from bank in banks.Include(p=>p.BankBranches)
            where bank.BankBranches.Where(y => y.CityId == filter.CityId).Count() > 0
            select bank;
    var list = banks.ToList();

Answer 2

banks = from bank in banks
        join bankBranche in m_banksRepository.BankBranches on bank.Id equals bankBranche.BankId
        where bankBranche.CityId == filter.CityId
        select bank;