c# - 使用LINQ过滤必要的数据

一直在和linq玩耍，但是我似乎无法做到这一点..这就是情况..可以说你有..

public class Job
{
    public DateTime? CreatedDate { get; set; }
}

public class Company
{
    public string Name { get; set; }
    public List<Job> Contract { get; set; }
}

现在，我要做的是填充“公司列表”，然后仅获取创建了合同的公司。让我们说一月..类似这样的事情。

String[] MonthName = { "January", "February", "March", "April", "May", "June", "July", "Agust", "September", "October", "November", "December" };

List<Company> Companies = PopulateData();
List<Company> ValidCompany = Companies.Where(CompanyFilter => CompanyFilter.Contract.Any(ContractFilter => MonthName[ContractFilter.CreatedDate.Value.Month - 1] == "January")).ToList();

这可以正常工作，但它会返回所有合同，即使某些合同不在“一月”中。我错过了一步吗？

最佳答案

原始帖子：

List<Company> ValidCompany = (
   from c in Companies
   let janContracts = c.Contracts
      .Where(con => MonthName[con.CreatedDate.Value.Month - 1] == "January")
   where janContracts.Any()
   select new Company
   {
       Name = c.Name,
       Contracts = janContracts.ToList()
   }).ToList();

更新：扩展方法

var janCompanies = Companies.Select(c=>
    new Company
    {
       Name = c.Name,
       Contracts = c.Contracts
           .Where(con => MonthName[con.CreatedDate.Value.Month - 1] == "January")
           .ToList()
    });
List<Company> ValidCompany = janCompanies
    .Where(c=>c.Contracts.Any())
    .ToList();