MVC中的ViewData、ViewBag和TempData

時間 2019-12-06

標籤 mvc viewdata viewbag tempdata 简体版

原文原文鏈接

1、ViewBag和ViewData的定義html

public dynamic ViewBag { get; }  
public ViewDataDictionary ViewData { get; set; }  
public dynamic ViewBag { get; }
public ViewDataDictionary ViewData { get; set; }

2、ViewBag和ViewData的區別web

viewdata	viewbag
它是key/value字典集合	它是dynamic類型對象
從asp.net mvc1就有了	從asp.netmvc3纔有
基於asp.netframework 3.5	基於asp.net framework4.0
viewdata比viewbag快	viewbag比viewdata慢
頁面查詢數據時須要轉換合適的類型	在頁面查詢數據時不須要轉換合適的類型
有一些類型轉換代碼	可讀性較好

ViewBag再也不是字典的鍵值對結構，而是dynamic動態類型，它會在程序運行的時候動態解析。session

 1 　　　　　　ViewBag.NumberObjs = new string[] { "one", "two", "three" };  
 2           ViewData["NumberArrs"] = new string[] { "one", "two", "three" };  
 3  
 4           //正確，dynamic類型的解析做用，foreach可使用  
 5           foreach (var item in ViewBag.NumberObjs)  
 6            {  
 7  
 8             }    
 9             //錯誤：foreach語句不可做用於object類型對象上  
10            foreach (var item in ViewData["NumberArrs"])  
11             {  
12  
13             }

一、ViewBag其實本質就是ViewData，只是多了層Dynamic控制。因此，使用何種方式徹底取決於你的我的愛好。mvc

二、ViewBag和ViewData僅針對當前Action中有效，生命週期和view相同。asp.net

3、TempDataspa

保存在session中，Controller每次執行請求時，會從session中獲取tempdata，然後清空session，獲取完tempdata數據，雖然保存在內部字典中。可是字典中每一個條目訪問一次後就從字典中刪除。所以Tempdata數據最多隻能通過一次controller傳遞，而且每一個元素最多隻能訪問一次，以後刪除。.net

4、舉例code

在Controller中使用ViewData:htm

<pre name="code" class="csharp">public ActionResult UsingViewData()
        {
            ViewData["Title"] = "Using ViewData";
            ViewData["ProjectName"] = "My Test Project";
            ViewData["ProjectDescription"] = "This is TestProject 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();
        }

<div><span style="color: rgb(35, 35, 35); font-family: Verdana, Arial, helvetica, sans-seriff; font-size: 14px; line-height: 25px; orphans: 2; text-align: -webkit-auto; widows: 2;">對應UsingViewData View的cshtml:</span></div><pre name="code" class="html">@{
    ViewBag.Title = "UsingViewData";
}

<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   : @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>

ViewBag controller：對象

        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.doyjoy");
            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();
        }

對應的頁面：

@{
    ViewBag.Title = "UsingViewBag";
}

<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   : @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>