[ASP.Net MVC 类库探索] AcceptVerbsAttribute 类

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[AttributeUsageAttribute(AttributeTargets.Method, AllowMultiple = false, Inherited = true)]public sealed class AcceptVerbsAttribute : ActionMethodSelectorAttribute

这是个特性类，可以作为特性修饰Action方法，这个特性指定了可以访问Action方法的HttpMethod方法(HttpMethod也被称为HttpVerb)，常见的HttpMehod有GET和POST，如果访问Action的HttpMethod不在特性指定的范围内，将返回HTTP 404错误

 

从这个类的源代码中可以看出，该类有两个构造函数，分别是接受HttpVerb枚举和一组变参String，其中HttpVerb枚举是Flag特性的，也就是说可以使用"|"操作符来指定多个参数。

例如让某个Action可同时接受Get和Post的Http访问，可以按下面的代码实现：

 

[AcceptVerbs(HttpVerbs.Post|HttpVerbs.Get)]        public ActionResult About()        {                        return View();        }

 

也可以按下面的代码实现：

 

[AcceptVerbs("POST","GET")]        public ActionResult About()        {                        return View();        }

 

下面是摘自CodePlex的该类的源代码：

 

/* **************************************************************************** * * Copyright (c) Microsoft Corporation. All rights reserved. * * This software is subject to the Microsoft Public License (Ms-PL).  * A copy of the license can be found in the license.htm file included  * in this distribution. * * You must not remove this notice, or any other, from this software. * * ***************************************************************************/namespace System.Web.Mvc {    using System;    using System.Collections.Generic;    using System.Collections.ObjectModel;    using System.Diagnostics.CodeAnalysis;    using System.Linq;    using System.Reflection;    using System.Web.Mvc.Resources;    [SuppressMessage("Microsoft.Design", "CA1019:DefineAccessorsForAttributeArguments",        Justification = "The accessor is exposed as an ICollection<string>.")]    [AttributeUsage(AttributeTargets.Method, AllowMultiple = false, Inherited = true)]    public sealed class AcceptVerbsAttribute : ActionMethodSelectorAttribute {        public AcceptVerbsAttribute(HttpVerbs verbs)            : this(EnumToArray(verbs)) {        }        public AcceptVerbsAttribute(params string[] verbs) {            if (verbs == null || verbs.Length == 0) {                throw new ArgumentException(MvcResources.Common_NullOrEmpty, "verbs");            }            Verbs = new ReadOnlyCollection<string>(verbs);        }        public ICollection<string> Verbs {            get;            private set;        }        private static void AddEntryToList(HttpVerbs verbs, HttpVerbs match, List<string> verbList, string entryText) {            if ((verbs & match) != 0) {                verbList.Add(entryText);            }        }        internal static string[] EnumToArray(HttpVerbs verbs) {            List<string> verbList = new List<string>();            AddEntryToList(verbs, HttpVerbs.Get, verbList, "GET");            AddEntryToList(verbs, HttpVerbs.Post, verbList, "POST");            AddEntryToList(verbs, HttpVerbs.Put, verbList, "PUT");            AddEntryToList(verbs, HttpVerbs.Delete, verbList, "DELETE");            AddEntryToList(verbs, HttpVerbs.Head, verbList, "HEAD");            return verbList.ToArray();        }        public override bool IsValidForRequest(ControllerContext controllerContext, MethodInfo methodInfo) {            if (controllerContext == null) {                throw new ArgumentNullException("controllerContext");            }            string incomingVerb = controllerContext.HttpContext.Request.HttpMethod;            return Verbs.Contains(incomingVerb, StringComparer.OrdinalIgnoreCase);        }    }}