.Net MVC3之1：前台异步获取json数据的实例(1)

时间：2022-01-26 20:34:55
在mvc3中，最让人称道的当然还是路由的方便与先进之处，类似于java中的mvc，加载每一个页面（包括首页），都要先运行该页面对应的后台controller，处理页面的初始化数据（mvc中的数据传递问题这里不再讲述）、域名读取、权限操作等，然后返回相应的页面。本篇文章讲述如何从mvc的前台页面中异步获取后台的json数据。
1.建一个mvc3的项目，取名叫MVC3Test（事先安装mvc3 version：1.13.113.0）
.Net MVC3之1：前台异步获取json数据的实例(1)
2.修改About.cshtml,如下代码
.Net MVC3之1：前台异步获取json数据的实例(1).Net MVC3之1：前台异步获取json数据的实例(1)About.cshtml
@{
ViewBag.Title = "About Us";
}
 < script type ="text/javascript" >
$( function () {
$.ajax({
url: " /Home/GetSchools " ,
type: " POST " ,
contentType: " application/json; charset=utf-8 " ,
data: " {} " ,
dataType: " json " ,
success: function (data) {
$( " #sltSchool " ).empty();
$( " #sltSchool " ).html(data);
},
error: function ErrorCallback(XMLHttpRequest, textStatus, errorThrown) {
alert(errorThrown + " : " + textStatus);
}
});
 // Get the departments depend on the school
$( " #sltSchool " ).change( function () {
GetDepartments($( " #sltSchool " ).val());
});
});

 function GetDepartments(sId) {
$.ajax({
url: " /Home/GetSecondCatalog " ,
type: " POST " ,
contentType: " application/json; charset=utf-8 " ,
data: " {schoolId: " + sId + " } " ,
dataType: " json " ,
success: function (data) {
$( ' #sltDepartment ' ).empty();
$( ' #sltDepartment ' ).html(data);
},
error: function ErrorCallback(XMLHttpRequest, textStatus, errorThrown) {
alert(errorThrown + " : " + textStatus);
}
});
}
 </ script >
< div >
< h2 >
About </ h2 >
< p >
Put content here.
 </ p >
< div >
< span >
< label >
School :
 </ label >
< select id ="sltSchool" >
< option value ="-1" > select... </ option >
</ select ></ span > < span style ="margin-left: 50px" >
< label >
Department : </ label >
< select id ="sltDepartment" >
< option value ="-1" > select... </ option >
</ select >
</ span >
</ div >
</ div >
3.创建几个model
 (1) TestSchool.cs
.Net MVC3之1：前台异步获取json数据的实例(1).Net MVC3之1：前台异步获取json数据的实例(1)TestSchool
using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Web;

 namespace MVC3Test.Models
{
 public class TestSchool
{
 public int Id { get ; set ; }
 public string Name { get ; set ; }
}
}
 (2) TestSchoolDepartment.cs
.Net MVC3之1：前台异步获取json数据的实例(1).Net MVC3之1：前台异步获取json数据的实例(1)TestSchoolDepartment.cs
using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Web;

 namespace MVC3Test.Models
{
 public class TestSchoolDepartment
{
 public int Id { get ; set ; }
 public int SchoolId { get ; set ; }
 public string Name { get ; set ; }
}
}
 (3) TestModels.cs
.Net MVC3之1：前台异步获取json数据的实例(1).Net MVC3之1：前台异步获取json数据的实例(1)TestModels.cs
using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Web;

 namespace MVC3Test.Models
{
 public class TestModels
{
 public static List < TestSchool > GetAllSchools()
{
 return new List < TestSchool > ()
{
 new TestSchool{Id = 1 ,Name = " ABC " },
 new TestSchool{Id = 2 ,Name = " DEF " },
 new TestSchool{Id = 3 ,Name = " HIJ " },
 new TestSchool{Id = 4 ,Name = " LMN " }
};
}

 public static List < TestSchoolDepartment > GetAllDepartment()
{
 return new List < TestSchoolDepartment > ()
{
 new TestSchoolDepartment{Id = 1 ,SchoolId = 1 ,Name = " ABC_D1 " },
 new TestSchoolDepartment{Id = 2 ,SchoolId = 1 ,Name = " ABC_D2 " },
 new TestSchoolDepartment{Id = 3 ,SchoolId = 1 ,Name = " ABC_D3 " },
 new TestSchoolDepartment{Id = 4 ,SchoolId = 2 ,Name = " DEF_D1 " },
 new TestSchoolDepartment{Id = 5 ,SchoolId = 2 ,Name = " DEF_D2 " },
 new TestSchoolDepartment{Id = 6 ,SchoolId = 3 ,Name = " HIJ_D1 " },
 new TestSchoolDepartment{Id = 7 ,SchoolId = 3 ,Name = " HIJ_D2 " },
 new TestSchoolDepartment{Id = 8 ,SchoolId = 3 ,Name = " HIJ_D3 " },
 new TestSchoolDepartment{Id = 9 ,SchoolId = 3 ,Name = " HIJ_D4 " },
 new TestSchoolDepartment{Id = 10 ,SchoolId = 4 ,Name = " LMN_D1 " }
};
}

 public static List < TestSchoolDepartment > GetDepartmentBySchoolId( int schoolId)
{
List < TestSchoolDepartment > testSchoolDepartment = new List < TestSchoolDepartment > ();
 foreach (TestSchoolDepartment department in GetAllDepartment())
{
 if (department.SchoolId == schoolId)
{
testSchoolDepartment.Add(department);
}
}
 return testSchoolDepartment;
}
}
}
4.由于About是在Home页面里的，所以它的controller应该在HomeController里，我们添加两个controller，如下：
.Net MVC3之1：前台异步获取json数据的实例(1).Net MVC3之1：前台异步获取json数据的实例(1)HomeController.cs
using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Web;
 using System.Web.Mvc;
 using MVC3Test.Models;
 using System.Text;

 namespace MVC3Test.Controllers
{
 public class HomeController : Controller
{
 public ActionResult Index()
{
ViewBag.Message = " Welcome to ASP.NET MVC! " ;

 return View();
}

 public ActionResult About()
{
 return View();
}

[HttpPost]
 public JsonResult GetSchools()
{
StringBuilder sb = new StringBuilder();
sb.Append( " <option value=\"-1\">select...</option> " );
 foreach (var item in TestModels.GetAllSchools())
{
sb.AppendFormat( " <option value=\"{0}\">{1}</option> " , item.Id, item.Name);
}
 string result = sb.ToString();
 return this .Json(result, JsonRequestBehavior.AllowGet);
}

[HttpPost]
 public JsonResult GetSecondCatalog( int schoolId)
{
StringBuilder sb = new StringBuilder();
sb.Append( " <option value=\"-1\">select...</option> " );
 foreach (var item in TestModels.GetDepartmentBySchoolId(schoolId))
{
sb.AppendFormat( " <option value=\"{0}\">{1}</option> " , item.Id, item.Name);
}
 string result = sb.ToString();
 return this .Json(result, JsonRequestBehavior.AllowGet);
}
}
}
好了，所有的代码都已完成，现在只要编译、运行项目即可。
……欢迎留言！！
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