过滤LINQ中的相关表

问题描述

| 假设我有一个公司表，一个雇员表，并且雇员表有一个到公司表的FK列。查询公司并返回相关员工非常容易。

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。但是如何过滤上面查询中返回的员工。例如，仅包括那些Employed列为true的员工？ 我想归还所有公司，只保留那些目前受雇的员工。     

解决方法

        检索受雇的公司及其雇员：

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

像这样使用：

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

根据您的评论的另一种方法，您需要在其他地方对此进行过滤：

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“ 5”数据对象生成的部分类：

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

    ,        我不确定您想对员工做什么，但这是一种遍历员工的方法：

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
    }
}

    ,        使用查询语法：

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