Asp.net MVC中的ViewData與ViewBag

Asp.net MVC中的ViewData與ViewBag

在Asp.net MVC 3 web應用程序中，咱們會用到ViewData與ViewBag，對比一下：

 

ViewData	ViewBag
它是Key/Value字典集合	它是dynamic類型對像
從Asp.net MVC 1 就有了	ASP.NET MVC3 纔有
基於Asp.net 3.5 framework	基於Asp.net 4.0與.net framework
ViewData比ViewBag快	ViewBag比ViewData慢
在ViewPage中查詢數據時須要轉換合適的類型	在ViewPage中查詢數據時不須要類型轉換
有一些類型轉換代碼	可讀性更好

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(); }

對應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> 

而後是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(); }

對應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> 

後面是在Controller中使用ViewBag:

public ActionResult UsingViewBagInControlAndViewDataInView() { ViewBag.Title = " Using ViewBag In Control And ViewData In View"; 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(); }

在UsingViewBagInControlAndViewDataInView.cshtml中使用ViewData來取值：

<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> 

反過來是這樣的:

public ActionResult UsingViewDataInControlAndViewBagInView() { ViewData["Title"] = " Using ViewData In Control And ViewBag In View"; 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(); }

在UsingViewDataInControlAndViewBagInView.cshtml 的View中使用ViewBag來取值:

<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> 

這樣對比看上去會比較清楚一些。在源代碼中的ViewBag是這樣的屬性:

public dynamic ViewBag {
    get { if (_dynamicViewData == null) { _dynamicViewData = new DynamicViewDataDictionary(() => ViewData); } return _dynamicViewData; } }

ViewData是：

public ViewDataDictionary ViewData { get { if (_viewData == null) { SetViewData(new ViewDataDictionary()); } return _viewData; } set { SetViewData(value); } }

具體細節在這兒不深刻了，這裏只是拋磚引玉。但願對您Asp.net MVC開發有幫助。

 

做者：Petter Liu
出處：http://www.cnblogs.com/wintersun/
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