MVC初体验-EF查询（Lambda的用法）（18）

namespace T1_EF.Controllers
{
    public class CustomersController : Controller
    {
        // GET: Customers
        public ActionResult Index()
        {
            //NorthwindEntities northwind = new NorthwindEntities();
            //var list = northwind.Customers.Select(c =>c);
            //建议使用下面这种写法，面向抽象编程，使用多态，并且更灵活
            //DbContext dbContext = new NorthwindEntities();
            //var list = dbContext.Set().Select(c => c);

            //使用Linq练习操作
            dynamic list;
            DbContext db = new NorthwindEntities();
            //基本查询
            //list = from customer in db.Set() select customer;

            //单条件查询
            //list = from customer in db.Set() where customer.Country == "USA" select customer;  

            //多条件查询
            //list = from customer in db.Set()
            //       where customer.Country == "USA" || customer.Country == "Canada"
            //       select customer;

            //查询单列（这样就不能使用强类型视图了）
            //list = from customer in db.Set() select customer.Country;

            //查询多列（将select后换为匿名对象或者要展示的对象）（建议新增viewModel作为视图对象，否则在前台数据必须进行反序列化操作）
            //list = from customer in db.Set() select new CustomerModel{ ContactName= customer.ContactName,CompanyName= customer.CompanyName };

            //分页,Skip就是跳过元素，Take就是要返回排在前面的几个元素，一般与OrderBy排序使用（注意：是方法特有的，不是Linq写法）
            list = (from customer in db.Set() select
                   customer).OrderBy(c => c.CompanyName).Skip(5).Take(15);

            ViewData.Model = list;
            return View();
        }

        public ActionResult FuncTionIndex()
        {
            //使用方法进行查询
            DbContext db = new NorthwindEntities();

            //返回全部数据
            var list = db.Set();

            //单条件查询(像JQuery的树一样叠加)
            //var list1 = list.Where(c => c.Country == "USA");

            //多条件
            //var list1 = list.Where(c => c.Country == "USA" || c.Country == "Canada");

            //单列或者多列查询
            //var list1 = list.Select(c => 
            //new CustomerModel { CompanyName = c.CompanyName, ContactName = c.ContactName });

            ViewData.Model = list1;
            return View();
        }
    }
}

@model IEnumerableT1_EF.Models.Customers>
@*@model IEnumerableT1_EF.ViewModels.CustomerModel>*@
@{
    Layout = null;
}

DOCTYPE html>

html>
head>
    meta name="viewport" content="width=device-width" />
    title>FuncTionIndextitle>
head>
body>
    div>
        table border="1">
            tr>
                td>联系人姓名td>
                td>客户公司td>
                td>客户属国td>
            tr>
            @foreach (var item in Model)
            {
                tr>
                    td>@item.ContactNametd>
                    td>@item.CompanyNametd>
                    td>@item.Countrytd>
                tr>
            }
        table>
    div>
body>
html>