HTML Forms概述

<form action="api/values" method="post">

默认的method是GET，如果使用GET，表单数据被编码到URI中作为查询字符串；如果使用POST，表单数据放在Request body中，enctype属性指定编码类型：

编码方式(enctype)	描述
application/x-www-form-urlencoded	表单数据被编码成name/value形式，默认的编码方式
multipart/form-data	表单数据被编码成多部分的MIME消息，上传文件时使用

application/x-www-form-urlencoded

POST http://localhost:38899/api/updates/complex HTTP/1.1

Accept: text/html, application/xhtml+xml, /

User-Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0)

Content-Type: application/x-www-form-urlencoded

Content-Length: 47

status=Shopping+at+the+mall.&date=6%2F15%2F2012

注意：

默认情况下WebAPI获得复杂类型的参数使用Request body中，简单参数从URI中，可以使用[FromBody]强制从Request body中获取。由于WebAPI最多读取Request body一次，所以action仅有一个参数是来自Request body，如果需要获取多个值从Request body可以使用复杂类型。

对于简单参数，在Request body中消息的格式：

=value

multipart/form-data

POST http://localhost:50460/api/values/1 HTTP/1.1

User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:12.0) Gecko/20100101 Firefox/12.0

Accept: text/html,application/xhtml+xml,application/xml;q=0.9,/;q=0.8

Accept-Language: en-us,en;q=0.5

Accept-Encoding: gzip, deflate

Content-Type: multipart/form-data; boundary=---------------------------41184676334

Content-Length: 29278

-----------------------------41184676334

Content-Disposition: form-data; name="caption"

Summer vacation

-----------------------------41184676334

Content-Disposition: form-data; name="image1"; >filename="GrandCanyon.jpg"

Content-Type: image/jpeg

(Binary data not shown)

-----------------------------41184676334--

• Content-Disposition:包含上传控件的名字、上传的文件的名字

• Content-Type：描述了这部分数据的类型。默认是text/plain可以省略

  上传的一个demo

   public class UploadController : ApiController
  
       {
  
           public async Task<HttpResponseMessage> PostFormData()
  
           {
  
               if (!Request.Content.IsMimeMultipartContent())
  
               {
  
                   throw new HttpResponseException(HttpStatusCode.UnsupportedMediaType);
  
               }
  
               string root = HttpContext.Current.Server.MapPath("~/App_Data");
  
               var provider = new MultipartFormDataStreamProvider(root);
  
               try
  
               {
  
                   await Request.Content.ReadAsMultipartAsync(provider);
  
                   foreach (MultipartFileData file in provider.FileData)
  
                   {
  
                       //文件名
  
                       Trace.WriteLine(file.Headers.ContentDisposition.FileName);
  
                       //服务端存储文件路径
  
                       Trace.WriteLine("Server file path:"+file.LocalFileName);
  
                   }
  
                   //对应的name/value
  
                   foreach (var key in provider.FormData.AllKeys)
  
                   {
  
                       foreach (var val in provider.FormData.GetValues(key))
  
                       {
  
                           Trace.WriteLine(string.Format("{0}: {1}", key, val));
  
                       }
  
                   }
  
                   return Request.CreateResponse(HttpStatusCode.OK);
  
               }
  
               catch (Exception e)
  
               {
  
                   return Request.CreateErrorResponse(HttpStatusCode.InternalServerError,e);
  
                   throw;
  
               }
  
           }
  
       }