Linq问题使我疯狂ٌ从Child Of Child Table中获取数据 [英] Linq Problem make me crazy ٌretreve Data from Child Of Child Table

问题描述

我有一个LINQ小问题，使我发疯
我是编程领域的小程序员"的新手.
我需要在编码中使用我的样式提供快速，简单的答案.
我的问题是
假设我有这个数据库

I have a small LINQ problem make me crazy
I am new in the field of programming "Small Programmer".
Plz I need fast ,simple answer using my Style in coding.
My problem Is
Suppose if I have the this database

City Table :  City_ID As PK ,City_Name .
Department Table : City_ID As FK ,Dept_ID As PK ,Dept_Name .
Employee Table :Dept_ID FK ,Emp_ID As PK ,Emp_Name .

1-如果我在字符串C中有城市名称；
我要撤消在放置在城市中的各个部门中工作的所有相关员工姓名，这些城市中的城市名称都在字符串C中；
2-如果我在字符串E中有雇员姓名；
我想撤退该员工所在的城市名称；
我的编码风格是:
-------------------------------------------------- ---------------------------------
使用像我的简单示例一样的Datacontext检索字符串E中具有雇员姓名的部门名称；

1- If I have City Name In string C;
I want To retreve All Assosiated Employee Names That Works In Depaartments Placed In City that have City Name That In string C ;
2- If I have Employee Name In string E;
I want To retreve City Name where That Employee Placed In ;
my Style in coding Is:
-----------------------------------------------------------------------------------
Using Datacontext Like My simple Example here to Retreve Department name that have Employee Name In string E ;

public partial class _Default : System.Web.UI.Page
{
    ProDataContext M = new ProDataContext();//Object for Database
    protected void Page_Load(object sender, EventArgs e)
    {
        string E;
        string D = M.Departments.Where(x => x.Dep_ID == M.Employees.Where(n => n.Emp_Name == E).Single().Dep_ID).Single().Dep_Name;
     }

}

-------------------------------------------------- ----------------------------------

谢谢....


[edit]整理出代码块-OriginalGriff [/edit]

------------------------------------------------------------------------------------

Thanx.....


[edit]Code blocks sorted out - OriginalGriff[/edit]

推荐答案

// Solution Number 1:  (Get Employees)
DataClasses3DataContext db = new DataClasses3DataContext();
            var tbl = from p in db.Employees
                      where p.Department.City.City_Name == txtCityName.Text
                      select p;


// Solution Number 2: (Get City Name)
DataClasses3DataContext db = new DataClasses3DataContext();
            var tbl = (from p in db.Employees
                       where
                          p.Emp_Name == txtEmployeName.Text
                       select p).Select(p => p.Department.City);
            dataGridView1.DataSource = tbl;

希望这对您有帮助
哈米德·诺阿迪(Hamid Noahdi)

Wish this helps you
Hamid Noahdi

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