LINQ中的篩選器相關表格

Question

假設我有一張公司表格，一張僱員表格，而僱員表格的公司表格中有一張FK列表。查詢公司並退還相關員工非常容易。

var companies = from c in Companies 
       select c; 

通過添加where子句來過濾這些公司非常容易。但是，我如何過濾上述查詢中返回的員工。例如，只包括那些僱員列在真實的僱員？

我想退回所有公司，只有當前僱用的員工。

Answer 1

要檢索利用它們的公司及其員工：

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

使用像這樣：

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

另一種方法，根據您的意見，您需要到別處過濾此：

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

最後，您可以修改爲您的生成的部分類數據對象：

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

Answer 2

我不知道你想與員工做什麼，但在這裏是通過他們迭代的方式：

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

使用查詢語法：

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