ASP.NET MVC中ViewData、ViewBag和TempData

1.ViewData

1.1 ViewData繼承了IDictionary<string, object>,因此在設置ViewData屬性時,傳入key必須要字符串型別,value可以是任意類型。

1.2 ViewData它只會存在這次的HTTP要求而已,而不像Session可以將數據帶到下HTTP要求。

    public class TestController : Controller{public ActionResult Index(){ViewData["msg"] = "123123";return View();}}

@{ViewBag.Title = "Index";
}<h2>頁面</h2>
<h2>@ViewData["msg"]</h2>

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2.ViewData的擴張屬性ViewData.Model

    public class TestController : Controller{public ActionResult Index(){User aa = new User() { Age = 1, Name = "linq" };//ViewData.Model = aa;return View(aa);}}

@{ViewBag.Title = "Index";
}
@model MvcApplication1.Models.User
<h2>頁面</h2>
<h2>@Model.Age</h2>
<h2>@Model.Name</h2>

3.ViewBag

3.1 嚴格來說ViewBag和ViewData的區別就是ViewBag是dynamic動態型別

    public class TestController : Controller{public ActionResult Index(){User aa = new User() { Age = 1, Name = "linq" };ViewBag.User = aa;return View();}}

@{ViewBag.Title = "Index";
}<h2>頁面</h2>
<h2>@ViewBag.User.Age</h2>
<h2>@ViewBag.User.Name</h2>

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4.TempData

4.1 TempData的信息在"一次網頁要求內有效"(ActionResult的返回類型必須為RedirectToRouteResult或RedirectToRouteResult類別,除此以外只要有取用的TempData的鍵值，默認就會在當次網頁就要求清除，但你只是單純設置了TempData的值，并沒有讀取行為的話，TempData還是會保留到下次使用)

    public class TestController : Controller{public ActionResult Index(string msg){TempData["msg"] = msg;return RedirectToAction("Index2");}public ActionResult Index2(){return View();}}

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