MVC教程四:Controller向View传值的几种方式

一、通过ViewData传值

MVC从开始版本就一直支持使用ViewData将Controller里面的数据传递到View。ViewData定义如下:

从上面的截图中可以看出,ViewData里面存的是字典类型的数据,在查看ViewDataDictionary的定义:

注意:ViewDataDictionary继承自IDictionary等接口,所以ViewData里面的Value值类型是object的,使用的时候需要进行类型转换。

Controller代码如下:

using MVCPassValue.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;

namespace MVCPassValue.Controllers
{
    public class ViewDataDemoController : Controller
    {
        // GET: ViewDataDemo
        public ActionResult Index(int? id)
        {
             //1、将字符串传递到View
             ViewData["Other"] = "通过ViewData传递字符串";
 
             // 2
             ViewData.Add(new KeyValuePair<string, object>("Id", id ?? -1));

             //3
             ViewData.Add("name", "tom");
             //4、将集合传递到View
             ViewData["Student"] = new List<Student>()
             {
               new Student
               {
                 ID = 1,
                 Name = "唐僧",
                 Age = 34,
                 Sex = "",
                 Email = "747976523@qq.com"
               },
               new Student
               {
                 ID = 2,
                 Name = "孙悟空",
                 Age = 635,
                 Sex = "",
                 Email = "sunwukong@163.com"
               },
               new Student
               {
                 ID = 3,
                 Name = "白骨精",
                 Age = 4532,
                 Sex = "",
                 Email = "74345523@qq.com"
               }
             }; 
            return View();
        }
    }
}

 

 View视图如下:

@using MVCPassValue.Models;
@{
    ViewBag.Title = "Index";
}
@{
    // 这里是使用的Razor语法,写的C#代码
    var stuViewData = ViewData["Student"] as List<Student>;//ViewData的value值是object类型的,这里需要进行类型转换
    var other = ViewData["Other"];
}

<div class="jumbotron">
    <p>
        <div style="background-color:darkgreen">
            <div>
                Controller通过ViewData向View传递数据
            </div>
            <div>
                1、传递字符串 other:@other;
            </div>
            <div>
                2、传递字符串 Id:@ViewData["Id"];
            </div>
            <div>
                3、传递字符串 name:@ViewData["name"];
            </div>
            <div>
                4、传递集合
                @foreach (var item in stuViewData)
                {
                    <div>
                        ID:@item.ID&nbsp;&nbsp;Name:@item.Name&nbsp;&nbsp;Age:@item.Age&nbsp;&nbsp;Sex:@item.Sex&nbsp;&nbsp;Email:@item.Email
                    </div>
                }
            </div>
        </div>
    </p>
</div>

 运行结果:

二、通过ViewBag传值

ViewBag是在MVC3中出现的,ViewBag是动态(dynamic)类型的。

 Controller代码:

using MVCPassValue.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;

namespace MVCPassValue.Controllers
{
    public class ViewBagDemoController : Controller
    {
        // GET: ViewBagDemo
        public ActionResult Index(int? id)
        {
            //1、将字符串传递到View
            ViewData["Other"] = "通过ViewData传递字符串";

            // 2
            ViewData.Add(new KeyValuePair<string, object>("Id", id ?? -1));

            //3
            ViewData.Add("name", "tom");
            //4、将集合传递到View
            ViewData["Student"] = new List<Student>()
             {
               new Student
               {
                 ID = 1,
                 Name = "唐僧",
                 Age = 34,
                 Sex = "",
                 Email = "747976523@qq.com"
               },
               new Student
               {
                 ID = 2,
                 Name = "孙悟空",
                 Age = 635,
                 Sex = "",
                 Email = "sunwukong@163.com"
               },
               new Student
               {
                 ID = 3,
                 Name = "白骨精",
                 Age = 4532,
                 Sex = "",
                 Email = "74345523@qq.com"
               }
             };


            #region 2、通过ViewBag传值
            ViewBag.name = "ViewBag";
            ViewBag.Stu1 = new Student()
            {
                ID = 5,
                Name = "沙悟净",
                Age = 567,
                Sex = "",
                Email = "4567890345@qq.com"
            };
            #endregion
            return View();
        }
    }
}

  Index视图代码:

@using MVCPassValue.Models;
@{
    ViewBag.Title = "Index";
}
@{
    var stuViewData = ViewData["Student"] as List<Student>;//ViewData的value值是object类型的,这里需要进行类型转换
    var other = ViewData["Other"];
}

@{
    var name = ViewBag.name;
    var stu = ViewBag.Stu1;//ViewBag是dynamic类型的,使用的时候不需要进行类型转换
    var stuList = ViewBag.Student;
}

<div class="jumbotron">
    <p>
        <div style="background-color:darkgreen">
            <div>
                Controller通过ViewData向View传递数据
            </div>
            <div>
                传递字符串 ViewData["name"]:@ViewData["name"];
            </div>
        </div>
    </p>

    <p>
        <div style="background-color:crimson">
            <div>
                Controller通过ViewBag向View传递数据
            </div>
            <div>
                1、传递字符串 ViewBag.name:@name;
            </div>
            <div>
                2、输出stu
                <div>
                    ID:@stu.ID&nbsp;&nbsp;Name:@stu.Name&nbsp;&nbsp;Age:@stu.Age&nbsp;&nbsp;Sex:@stu.Sex&nbsp;&nbsp;Email:@stu.Email
                </div>
                3、输出stuList
                @foreach (var item in stuList)
                {
                    <div>
                        ID:@item.ID&nbsp;&nbsp;Name:@item.Name&nbsp;&nbsp;Age:@item.Age&nbsp;&nbsp;Sex:@item.Sex&nbsp;&nbsp;Email:@item.Email
                    </div>
                }
            </div>
        </div>
    </p>
</div>

 运行结果;

看了上面的运行结果,你可能会提出如下的两个疑问:

1、Controller里面没有定义ViewBag.Student,为什么在这里可以使用呢?

这是因为ViewBag是从MVC3版本才开始出现的,为了兼容以前的ViewData,所以这里虽然没有定义ViewBag.Student,但是ViewBag可以使用ViewData里面定义的Student。

2、ViewData["name"]和ViewBag.name的值是一样的

在控制器里面明明设置的两个值是不同的,但是为什么这里都变成一样的了呢?这是因为ViewData和ViewBag的属性是重叠的,两者都是字典类型的,一切以后面定义的属性为准,即后面定义的会覆盖前面定义的。

三、通过TempData传值

先来看看下面的代码:

using MVCPassValue.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;

namespace MVCPassValue.Controllers
{
    public class TempDataDemoController : Controller
    {
        // GET: TempDataDemo
        public ActionResult Index()
        {
            ViewData["Name"] = "tom";
            ViewBag.Name = "Jon";
            TempData["Name"] = "Andi";
            TempData["Stu"] = new Student()
            {
                ID = 5,
                Name = "沙悟净",
                Age = 567,
                Sex = "",
                Email = "4567890345@qq.com"
            };
            return View();
        }
    }
}

 

index视图代码:

@using MVCPassValue.Models;
@{
    ViewBag.Title = "Index";
}
@{
    var stu = TempData["Stu"] as Student;
}

<div class="jumbotron">
    <p>
        <div style="background-color:darkgreen">
            <div>
                传递字符串 ViewData["Name"]:@ViewData["Name"];
            </div>
        </div>
    </p>

    <p>
        <div style="background-color:crimson">
            <div>
                1、传递字符串 ViewBag.Name:@ViewBag.Name;
            </div>
        </div>
    </p>
    <p>
        <div style="background-color:crimson">
            <div>
                1、传递字符串 TempData["Name"]:@TempData["Name"];
            </div>
            2、输出stu
            <div>
                ID:@stu.ID&nbsp;&nbsp;Name:@stu.Name&nbsp;&nbsp;Age:@stu.Age&nbsp;&nbsp;Sex:@stu.Sex&nbsp;&nbsp;Email:@stu.Email
            </div>
        </div>
    </p>
</div>

 允许结果:

从上面的结果中可以看出:TempData的属性值不会覆盖上面定义的属性值。那TempData还有什么作用呢?在看下面的代码:

using MVCPassValue.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;

namespace MVCPassValue.Controllers
{
    public class TempDataDemoController : Controller
    {
        // GET: TempDataDemo
        public ActionResult Index(int? id)
        {
            ViewData["Name"] = "tom";
            ViewBag.Name = "Jon";
            TempData["Name"] = "Andi";
            TempData["Stu"] = new Student()
            {
                ID = 5,
                Name = "沙悟净",
                Age = 567,
                Sex = "",
                Email = "4567890345@qq.com"
            };

            if (id == null)
                return RedirectToAction("TempDataTest");
            else
                return View();
        }

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

 TempDataTest视图代码:

@using MVCPassValue.Models;
@{
    ViewBag.Title = "TempDataTest";
}
@{
    var stu = TempData["Stu"] as Student;
}

<h2>TempDataTest</h2>
<h3>ViewData["id"]:@ViewData["Id"]</h3>
<h3>ViewData["Name"]:@ViewData["Name"]</h3>
<h3>TempData["Name"]:@TempData["Name"];</h3>
<h3>ID:@stu.ID&nbsp;&nbsp;Name:@stu.Name&nbsp;&nbsp;Age:@stu.Age&nbsp;&nbsp;Sex:@stu.Sex&nbsp;&nbsp;Email:@stu.Email</h3>

 运行结果:

 

你会发现这时ViewData取不到数据了,只有TempData可以取到数据,可以得出TempData和ViewData、ViewBag的区别:

TempData是基于session存储的,单次请求数据不丢失(ViewData和ViewBag会丢失),后台跨页面传值,只能用一次

四、Model传值

controller代码:

using MVCPassValue.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;

namespace MVCPassValue.Controllers
{
    public class ModelDemoController : Controller
    {
        // GET: ModelDemo
        public ActionResult Index()
        {
            return View(new Student()
            {
                ID = 5,
                Name = "沙悟净",
                Age = 567,
                Sex = "",
                Email = "4567890345@qq.com"
            });
        }
    }
}

 index视图代码:

@{
    ViewBag.Title = "Index";
}
@Model Student;

<h2>Index</h2>
<h3>ID:@Model.ID</h3>
<h3>Name:@Model.Name</h3>
<h3>Age:@Model.Age</h3>
<h3>Sex:@Model.Sex</h3>
<h3>Email:@Model.Email</h3>

 运行结果:

 

posted @ 2019-01-08 00:37  .NET开发菜鸟  阅读(2022)  评论(0编辑  收藏  举报