、Models
namespace 下拉列表联动显示_Car表_.Models
{
public class ProductorBF
{
private MyDBDataContext _context=new MyDBDataContext();
public List<productor> Select() //厂商全部显示
{
return _context.productor.ToList();
} }
} namespace 下拉列表联动显示_Car表_.Models
{
public class BrandBF
{
private MyDBDataContext _context = new MyDBDataContext();
public List<brand> Select() //品牌（系列）全部显示
{
return _context.brand.ToList();
}
public List<brand> SelectByProd(string prod) //根据汽车厂商查汽车品牌
{ var query = _context.brand.Where(P => P.prod_code == prod);
if (query.Count() > )
{
return query.ToList();
}
else
{
return null;
} }
}
} namespace 下拉列表联动显示_Car表_.Models
{
public class CarBF
{
private MyDBDataContext _context = new MyDBDataContext();
public List<car> Select() //汽车全部显示
{
return _context.car.ToList();
}
public List<car> SelectByBrand(string brand_code) //根据汽车品牌查具体汽车
{
var query = _context.car.Where(P => P.brand==brand_code);
if (query.Count() > )
{
return query.ToList();
}
else
{
return null;
}
}
}
} 、Controllers
namespace 下拉列表联动显示_Car表_.Controllers
{
public class HomeController : Controller
{ [HttpGet]
public ActionResult Index()
{
//厂家表(强类型)
List<productor> list =new ProductorBF().Select();
SelectList aaa = new SelectList(list,"prod_code","prod_name","p001"); //品牌表
List<brand> list1 = new BrandBF().SelectByProd("p001");
SelectList bbb1 = new SelectList(list1, "brand_code", "brand_name");
ViewBag.bbb = bbb1; //汽车表
List<car> cars = new CarBF().SelectByBrand("b001");
SelectList ccc1 = new SelectList(cars,"code","name");
ViewBag.ccc = ccc1; return View(aaa);
} [HttpPost]
public ActionResult Index(string prodcode,string brandcode,string carcode)
{
//厂家表(强类型)
List<productor> list1 = new ProductorBF().Select();
SelectList aaa = new SelectList(list1, "prod_code", "prod_name",prodcode); //品牌表
List<brand> list2 = new BrandBF().SelectByProd(prodcode);
SelectList bbb1 = new SelectList(list2,"brand_code","brand_name",brandcode);
ViewBag.bbb = bbb1; //汽车表
//两种情况：选厂商的时候，判断一下加载的系列在不在当前厂商下
//1、在的话，直接根据加载出来的系列代号查
//2、不在的话，根据新选的厂商加载出来系列的第一个查
var b = list2.Exists(P => P.brand_code == brandcode) ? brandcode : list2[].brand_code; //假设选的是P003，但是定位的Brand是B001，所有需要判断，如果品牌里的下拉列表里有一个代号等于传进来的brand，说明有，可以查；如果不包含，需要根据你提交的厂商查出来的品牌中的第一项来查
List<car> list3 = new CarBF().SelectByBrand(b);
SelectList ccc1 = new SelectList(list3,"code","name",carcode);
ViewBag.ccc = ccc1; return View(aaa);
} }
} 、Views
@using 下拉列表联动显示_Car表_.Models;
@model SelectList
@{
Layout = null;
} <!DOCTYPE html> <html>
<head>
<meta name="viewport" content="width=device-width" />
<title>Index</title>
</head>
<body>
<div>
@using (Html.BeginForm("Index", "Home", FormMethod.Post))
{
//new { onchange="document.forms[0].submit();"} 文本一旦改变整个表单会跟着变
@Html.DropDownList("prodcode", Model,new { onchange="document.forms[0].submit();"});
@Html.DropDownList("brandcode", ViewBag.bbb as SelectList,new { onchange="document.forms[0].submit();"});
@Html.DropDownList("carcode", ViewBag.ccc as SelectList); }
</div>
</body>
</html>
效果图：
