我在MVC 3中看到了ViewBag。这和MVC 2中的ViewData有什么不同?
当前回答
我能建议你不要用吗?
如果你想“发送”数据到你的屏幕上,发送一个强类型对象(又名ViewModel),因为它更容易测试。
如果你绑定到某种类型的“模型”,并拥有随机的“viewbag”或“viewdata”项,那么这会使自动化测试变得非常困难。
如果您正在使用这些,请考虑如何重构并仅使用ViewModels。
其他回答
在ViewBag内部,属性以名称/值对的形式存储在ViewData字典中。
注意:在MVC 3的大多数预发布版本中,ViewBag属性被命名为ViewModel,这段代码来自MVC 3发布说明:
有人建议我发布我发布的这个信息的来源,下面是来源: http://www.asp.net/whitepapers/mvc3-release-notes#_Toc2_4
MVC 2 controllers support a ViewData property that enables you to pass data to a view template using a late-bound dictionary API. In MVC 3, you can also use somewhat simpler syntax with the ViewBag property to accomplish the same purpose. For example, instead of writing ViewData["Message"]="text", you can write ViewBag.Message="text". You do not need to define any strongly-typed classes to use the ViewBag property. Because it is a dynamic property, you can instead just get or set properties and it will resolve them dynamically at run time. Internally, ViewBag properties are stored as name/value pairs in the ViewData dictionary. (Note: in most pre-release versions of MVC 3, the ViewBag property was named the ViewModel property.)
ViewBag vs MVC中的ViewData
http://royalarun.blogspot.in/2013/08/viewbag-viewdata-tempdata-and-view.html
ViewBag和ViewData的相似之处:
当您从控制器移动到视图时,有助于维护数据。用于 将数据从控制器传递到相应的视图。短寿命意味着 值在重定向发生时变为空。这是因为他们的目标 是提供一种在控制器和视图之间通信的方法。这是 服务器调用中的通信机制。
ViewBag和ViewData的区别:
ViewData是派生自的对象字典 viewdatdictionary类,并使用字符串作为键访问。ViewBag 动态属性是否利用了新的动态特性 在c# 4.0。ViewData需要对复杂的数据类型进行类型转换 检查空值以避免错误。ViewBag不需要 复杂数据类型的类型转换。
ViewBag & ViewData示例:
public ActionResult Index()
{
ViewBag.Name = "Arun Prakash";
return View();
}
public ActionResult Index()
{
ViewData["Name"] = "Arun Prakash";
return View();
}
视图呼叫
@ViewBag.Name
@ViewData["Name"]
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.
public ActionResult Index()
{
ViewBag.Name = "Monjurul Habib";
return View();
}
public ActionResult Index()
{
ViewData["Name"] = "Monjurul Habib";
return View();
}
In View:
@ViewBag.Name
@ViewData["Name"]
通过这种方式,我们可以让它使用这些值来将控制器之间的信息传递到带有TEMP DATA的其他页面
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