MVC3中 ViewBag、ViewData和TempData的使用和区别（转载）

在MVC3开始，视图数据可以通过ViewBag属性访问，在MVC2中则是使用ViewData。MVC3中保留了ViewData的使用。ViewBag 是动态类型（dynamic），ViewData 是一个字典型的（Dictionary）。

ViewBag和ViewData的区别：
ViewBag 不再是字典的键值对结构，而是 dynamic 动态类型，它会在程序运行的时候动态解析。所以在视图中获取它的数据时候不需要进行类型转换

ViewData	ViewBag
它是Key/Value字典集合	它是dynamic类型对像
从Asp.net MVC 1 就有了	ASP.NET MVC3 才有
基于Asp.net 3.5 framework	基于Asp.net 4.0与.net framework
ViewData比ViewBag快	ViewBag比ViewData慢
在ViewPage中查询数据时需要转换合适的类型	在ViewPage中查询数据时不需要类型转换
有一些类型转换代码	可读性更好

1、ViewData是字典类型，赋值方式用字典方式，通过key值读取对应的value， ViewData["myName"]

2、ViewBag是动态类型，使用时直接添加属性赋值即可 ViewBag.myName

3、ViewBag和ViewData只在当前Action中有效，等同于View

4、ViewData和ViewBag 中的值可以互相访问，因为ViewBag的实现中包含了ViewData

-------------------ViewBag简单应用------------------------------------------------

Contorller

[csharp] view plain copy

<pre class="csharp" name="code">using NewOjbect.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
namespace NewOjbect.Controllers
{
public class HomeController : Controller
{
public ActionResult Index()
{
ViewBag.UserName = "无盐海";
ViewBag.Age = "25";
ViewBag.Gender = 1;
string[] Itmes = new string[] { "中国", "美国", "德国" };
ViewBag.itemsA = Itmes;// viewbag是一个新的dynamic类型关键字的封装器 //ViewData["Items"] = items;
return View();
}
}
}

View

[html] view plain copy

<pre class="html" name="code"><html>
<head>
<meta name="viewport" content="width=device-width" />
<title>Test2</title>
</head>
<body>
<div>
用户名：<input type="text" id="UserName" name="UserName" value="@ViewBag.UserName" /></br>
年龄: <input type="text" id="age" name="age" [email protected] /></br>
性别：<input type="text" id="Gender" name="Gender" value="@ViewBag.Gender" /></br>
<button>提交</button>
>
@foreach (dynamic item in ViewBag.itemsA)
{
<p>@item</p>
}
</div>
</body>
</html>

---------------------复杂应用----------------------------------

在Controller中使用ViewData:

public ActionResult UsingViewData()
{
    
    ViewData["Title"] = " Using ViewData";
    ViewData["ProjectName"] = "My Test Project";
    ViewData["ProjectDescription"] = "This is Test Project to demo Viewdata and viewbag details";
    ViewData["StartDate"] = new DateTime(2011, 1, 1);
    ViewData["TotalPrice"] = 1000;
    ViewData["TotalDays"] = 100;
    Dictionary<string, string> stackholder = new Dictionary<string, string>();
    stackholder.Add("Client","Mr.  Client");
    stackholder.Add("Manager","Mr. Joy");
    stackholder.Add("Team Leader","Mr.Toy");
    stackholder.Add("Sr. developer", "Mr.dojoy");
    stackholder.Add("developer", "Mr. nodoy");
    ViewData["stackholder"] = stackholder;

    List<string> modules = new List<string>();
    modules.Add("Admin module");
    modules.Add("ShoppingCart module");
    modules.Add("CMS module");
    ViewData["modules"] = modules;
    return View();
}

对应UsingViewData View的cshtml:

<h1>@ViewData["Title"]</h1>
 <div>
   <div>
    <h2>Project Name : @ViewData["ProjectName"]</h2>
   </div>
   <div>
     ProjectDescription :   
     <p>"@ViewData["ProjectDescription"]".</p>
   </div>
   <div>
      Stack Holder :
      <br />

      <ul id="stakholder">
      @foreach ( var stakerholder in ViewData["stackholder"] as Dictionary<string, string> )
      {          
    <li>
        @stakerholder.Key &nbsp; : @stakerholder.Value
    </li>
      }
     </ul>
   </div>
   <div>
     Project Details:<br />
     <div>
       module List  :
       <ul id="modulelist">
      @foreach ( var module in ViewData["modules"] as List<string> )
      {          
    <li>
        @module
    </li>
      }
     </ul>
        
     </div>
     Project StartDate : @ViewData["StartDate"]  <br />
     Project TotalPrice: @ViewData["TotalPrice"] <br />
     Project TotaDays  : @ViewData["TotalDays"] 
   </div>
 </div>

然后是ViewBag:

public ActionResult UsingViewBag()
{

    ViewBag.Title = " Using ViewBag";
    ViewBag.ProjectName = "My Test Project";
    ViewBag.ProjectDescription = "This is Test Project to demo Viewdata and viewbag details";
    ViewBag.StartDate = new DateTime(2011, 1, 1);
    ViewBag.TotalPrice = 1000;
    ViewBag.TotalDays = 100;
    Dictionary<string, string> stackholder = new Dictionary<string, string>();
    stackholder.Add("Client", "Mr.  Client");
    stackholder.Add("Manager", "Mr. Joy");
    stackholder.Add("Team Leader", "Mr.Toy");
    stackholder.Add("Sr. developer", "Mr.dojoy");
    stackholder.Add("developer", "Mr. nodoy");
    ViewBag.stackholder = stackholder;

    List<string> modules = new List<string>();
    modules.Add("Admin module");
    modules.Add("ShoppingCart module");
    modules.Add("CMS module");
    ViewBag.modules = modules;
    return View();
}

对应View UsingViewBag 的cshtml的ViewBag:

<h1>@ViewBag.Title</h1>
 <div>
   <div>
    <h2>Project Name : @ViewBag.ProjectName</h2>
   </div>
   <div>
     ProjectDescription :   
     <p>"@ViewBag.ProjectDescription.</p>
   </div>
   <div>
      Stack Holder :
      <br />

      <ul id="stakholder">
      @foreach ( var stakerholder in ViewBag.stackholder )
      {          
    <li>
        @stakerholder.Key &nbsp; : @stakerholder.Value
    </li>
      }
     </ul>
   </div>
   <div>
     Project Details:<br />
     <div>
       module List  :
       <ul id="modulelist">
      @foreach ( var module in ViewBag.modules )
      {          
    <li>
        @module
    </li>
      }
     </ul>
        
     </div>
     Project StartDate : @ViewBag.StartDate.ToString("dd-MMM-yyyy") <br />
     Project TotalPrice: @ViewBag.TotalPrice  ₹  <br />
     Project TotaDays  : @ViewBag.TotalDays 
   </div>
 </div>

-------------------------------TempData----------------------------------------------------

同ViewData和ViewBag一样，TempData也可以用来向视图传递数据。只是ViewData和ViewBag的生命周期和View相同，只对当前View有用。而TempData则可以在不同的Action中进行传值，类似webform里的Seesion。如下：

public ActionResult Index()
{
ViewBag.hello = "hello,this is viewBag";
ViewData["hi"] = "hi,this is viewData";
TempData["abc"] = "this is tempdata";
return View();
}

然后在About视图里面调用：

<h2>关于</h2>
<p>
@ViewBag.hello
@ViewData["key"]
@TempData["abc"]
</p>

页面效果如下：

这里只获取到了TempData["abc"]的值,但是TempData的值在取了一次后则会自动删除，这时我再刷新页面，则TempData["abc"]为Null了。通过反编译查看代码，发现TempData数据在调用后则会自动删除。详情请看：http://www.cnblogs.com/tristanguo/archive/2009/04/06/1430062.html

mvc里面用session和tempdata，哪个好？看你实际的情况了。tempdata只是临时用来在不同action间传值用的，而session是打算长期会话保存状态的。

----------------------------------转载来源---------------------------------------------

简单应用

https://blog.csdn.net/Fanbin168/article/details/44803437

详细说明

http://www.cnblogs.com/bianlan/archive/2013/01/11/2857105.html

复杂应用

https://www.cnblogs.com/wintersun/archive/2012/01/21/2328563.html