LINQ中的筛选器相关表格

Question

假设我有一张公司表格，一张雇员表格，而雇员表格的公司表格中有一张FK列表。查询公司并退还相关员工非常容易。

var companies = from c in Companies 
       select c; 

通过添加where子句来过滤这些公司非常容易。但是，我如何过滤上述查询中返回的员工。例如，只包括那些雇员列在真实的雇员？

我想退回所有公司，只有当前雇用的员工。

Answer 1

要检索利用它们的公司及其员工：

var companies = from c in Companies 
       select new 
       { 
        Company = c, 
        EmployedPersons = c.Employees.Where(e => e.Employed) 
       }; 

使用像这样：

foreach (var company in companies) 
{ 
    Console.WriteLine("{0}", company.Company); 
    foreach (var employee in company.EmployedPersons) 
    { 
     Console.WriteLine("{0}", employee); 
    } 
} 

另一种方法，根据您的意见，您需要到别处过滤此：

public void DisplayEmployedPersons(Company company) 
{ 
    foreach (var employee in company.Employees.Where(e => e.Employed)) 
    { 
     Console.WriteLine("{0}", employee); 
    } 
} 

最后，您可以修改为您的生成的部分类数据对象：

public partial class Customer 
{ 
    public IEnumerable<Employee> CurrentEmployees 
    { 
     get { return this.Employees.Where(e => e.Employed); 
    } 
} 

Answer 2

我不知道你想与员工做什么，但在这里是通过他们迭代的方式：

var companies = from c in Companies 
       where c.Employees.Any(e => e.Employed) 
       select c; 

foreach (var company in companies) { 
    foreach (var employee in company.Employees.Where(e => e.Employed)) { 
     // your employed employees are iterated here 
    } 
} 

Answer 3

使用查询语法：

var companies = from c in Companies 
       from e in c.Employees 
       where e.Employed 
       select c;