我注意到ViewData和ViewBag之间的一个主要区别是:

ViewData:它将返回object，不管你给它赋了什么，需要再次类型转换回原始类型。

ViewBag:它足够聪明，可以返回你分配给它的确切类型，不管你分配的是简单类型(即int，字符串等)还是复杂类型。

例如:控制器代码。

 namespace WebApplication1.Controllers
{
    public class HomeController : Controller
    {
        public ActionResult Index()
        {
            Products p1 = new Products();
            p1.productId = 101;
            p1.productName = "Phone";
            Products p2 = new Products();
            p2.productId = 102;
            p2.productName = "laptop";

            List<Products> products = new List<Products>();
            products.Add(p1);
            products.Add(p2);
            ViewBag.Countries = products;
            return View();
        }
    }
    public class Products
    {
        public int productId { get; set; }
        public string productName { get; set; }
    }
}

视图代码。

<ul>
            @foreach (WebApplication1.Controllers.Products item in ViewBag.Countries)
            {
            <li>@item.productId &nbsp;&nbsp;&nbsp;@item.productName</li>
            }
        </ul>

屏幕输出。

下面是关于ViewData, ViewBag, TempData和Session的点对点差异。 信贷/ askforprogram复制。在这里，遵循我没有提到的代码示例的链接。

ViewData in MVC ViewData is property of ControllerBase class. ViewData is a type of dictionary object. ViewData is key-value dictionary collection. ViewData was introduced in MVC 1.0 version. ViewData works with .Net framework 3.5 and above. Need to do type conversion of code while enumerating. ViewData object keeps data only for current request. ViewBag in MVC ViewBag is property of ControllerBase class. ViewBag is a type of dynamic object. ViewBag is a type of object. ViewBag was introduced in MVC 3.0 version. ViewBag works with .Net framework 4.0 and above. ViewBag uses property and handles it, so no need to do type conversion while enumerating. ViewBag object keeps data only for current request. TempData in MVC TempData is property of ControllerBase class. TempData is a type of dictionary object. TempData is key-value dictionary collection. TempData was introduced in MVC 1.0 version. TempData works with .Net framework 3.5 and above. Need to do type conversion of code while enumerating. TempData object is used to data between current request and subsequent request. Session in MVC Session is property of Controller(Abstract Class). Session is a type of HttpSessionStateBase. Session is key-value dictionary collection. Session was introduced in MVC 1.0 version. TempData works with .Net framework 1.0 and above. Need to do type conversion of code while enumerating. Session object keeps data for all requests. Valid for all requests, never expires.

它使用c# 4.0动态特性。它实现了与viewdata相同的目标，应该避免使用强类型视图模型(与viewdata应该避免的方式相同)。

基本上它取代了魔法字符串:

ViewData["Foo"]

具有神奇属性:

ViewBag.Foo

你没有编译时安全性。

我继续指责微软在MVC中引入了这个概念。

属性的名称区分大小写。

public ActionResult Index()
{
    ViewBag.Name = "Monjurul Habib";
    return View();
}

public ActionResult Index()
{
    ViewData["Name"] = "Monjurul Habib";
    return View();
} 

In View:

@ViewBag.Name 
@ViewData["Name"] 

viewdata:是一个字典，用于存储视图和控制器之间的数据，你需要将视图数据对象转换为视图中相应的模型，以便能够从中检索数据…

ViewBag:是一个动态属性，在它的工作类似于视图数据，但它是更好的，因为它不需要在视图中使用它之前被强制转换为相应的模型…

有一些细微的区别，这意味着你可以使用ViewData和ViewBag与视图略有不同的方式。这篇文章http://weblogs.asp.net/hajan/archive/2010/12/11/viewbag-dynamic-in-asp-net-mvc-3-rc-2.aspx中概述了一个优点，并展示了在示例中可以通过使用ViewBag而不是ViewData来避免强制转换。