前面的Post有提到解決Web中表單重復提交的方法，實際上表單重復提交的問題不單是Asp.net，其它動態Page都有。讓我們看下面的圖示:
然后在刷新頁面時經常看到提示框在IE中:
Google Chrome:
Firefox:
最簡單的解決方法就是使用Post-Redirect-Get模式，就是Http-Post完后，馬上做Redirect操作，接下來那個頁面是Get。這時用戶強制按F5刷新也沒有用了。最終實現的效果圖：
那在Asp.net MVC中如何去做呢，看下面簡單View代碼：
一個包含兩個Input的表單:
<form method="post" id="form1" action="/Security/LoginVerify"> <p> UserName:<input type="text" id="fusername" name="fusername" /><br /> Password:<input type="password" id="fpassword" name="fpassword" /> <input type="submit" value="Sign-in" /> </p> </form>
Index Action 在這里做Get的操作, LoginVerify 在這里是Post的目標Action
[HttpPost] public ActionResult LoginVerify(string fusername, string fpassword) { return this.RedirectToAction("Index", "Security", new { fusername = fusername }); }
public ActionResult Index(string fusername) { ViewBag.UserName = fusername + " login success!"; return View(); }
對應請求時的HTTP Request RAW是這樣的:
POST http://localhost:91/Security/LoginVerify HTTP/1.1
Accept: text/html, application/xhtml+xml, */*
Referer: http://localhost:91/Security/Login
Accept-Language: en-US,zh-CN;q=0.5
User-Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0)
Content-Type: application/x-www-form-urlencoded
Accept-Encoding: gzip, deflate
Host: localhost:91
Content-Length: 71
Connection: Keep-Alive
Pragma: no-cache
Cookie: ASP.NET_SessionId=qwwlp4rmjnzbsq3ob4dmcg3q
Http Response RAW:
HTTP/1.1 302 Found
Cache-Control: private
Content-Type: text/html; charset=utf-8
Location: /Security?fusername=admin
Server: Microsoft-IIS/7.5
X-AspNetMvc-Version: 3.0
X-AspNet-Version: 4.0.30319
X-Powered-By: ASP.NET
Date: Sat, 24 Mar 2012 02:54:26 GMT
Content-Length: 142<html><head><title>Object moved</title></head><body>
<h2>Object moved to <a href="/Security?fusername=admin">here</a>.</h2>
</body></html>
在現在大多數的Web應用程序中都使用是Http 302的重定向。Http 1.1說明書中引用HTTP 303就是用來應對這種用戶提交表單后可以在瀏覽器安全的刷新場景。 HTTP 303 意義是這樣的：
Used to tell the client that the resource should be fetched using a different URL. This
new URL is in the Location header of the response message. Its main purpose is to
allow responses to POST requests to direct a client to a resource.
在Asp.net MVC可以這些去實現一個自定義ActionResult:
/// <summary> /// SeeOtherRedirectResult /// </summary> public class SeeOtherRedirectResult : ActionResult { private string _url; /// <summary> /// Initializes a new instance of the <see cref="SeeOtherRedirectResult"/> class. /// </summary> /// <param name="url">Target URL.</param> public SeeOtherRedirectResult(string url) { _url = url; } /// <summary> /// Enables processing of the result of an action method by a custom type that inherits from the <see cref="T:System.Web.Mvc.ActionResult"/> class. /// </summary> /// <param name="context">The context in which the result is executed. The context information includes the controller, HTTP content, request context, and route data.</param> public override void ExecuteResult(ControllerContext context) { context.HttpContext.Response.StatusCode = 303; context.HttpContext.Response.RedirectLocation = _url; } }
然后Action中使用它，來實現Http 303的重定向。：
[HttpPost] public ActionResult LoginVerify(string fusername, string fpassword) { return new SeeOtherRedirectResult(Url.Action("Index", "Security", new { fusername = fusername })); }
運行時，我們來看Http Response RAW:
HTTP/1.1 303 See Other
Cache-Control: private
Location: /Security?fusername=admin
Server: Microsoft-IIS/7.5
X-AspNetMvc-Version: 3.0
X-AspNet-Version: 4.0.30319
X-Powered-By: ASP.NET
Date: Sat, 24 Mar 2012 03:05:37 GMT
Content-Length: 0
完了，希望對您Web開發有幫助。如有任何問題請留言!
您可能感興趣的文章：
Asp.net MVC中防止HttpPost重復提交
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作者：Petter Liu
出處：http://www.cnblogs.com/wintersun/
本文版權歸作者和博客園共有，歡迎轉載，但未經作者同意必須保留此段聲明，且在文章頁面明顯位置給出原文連接，否則保留追究法律責任的權利。
該文章也同時發布在我的獨立博客中-Petter Liu Blog。