最近在做这个，一开始也是不明白为什么给个URL带着两个参数就直接上传了，网上看了很多都是PHP，但是PHP没看过是不会 的
所以就一直在找网上什么Demo之类的讲解，最后还是不错找到了一个比较好理解的例子。
整个过程是这样的：
1、我们首先建一个项目
2、项目建好后就一个简单的file控件和一个submit提交按钮我们这里要用表单提交
上代码：
<html>
<head>
<title>qweqw</title>
</head>
<body>
@using (Html.BeginForm("Upload", "Source", FormMethod.Post, new { enctype = "multipart/form-data" }))
{
<text>选择上传文件：</text><input name="file" type="file" id="file" />
<br />
<br />
<input type="submit" name="Upload" value="Upload" />
}
</body>
</html>
3、前台完了那就到后台了对吧
看代码：
[HttpPost]
public ActionResult Upload(FormCollection form)
{
if (Request.Files.Count == 0)
{
//Request.Files.Count 文件数为0上传不成功
return View();
}
var file = Request.Files[0];
if (file.ContentLength == 0)
{
//文件大小大（以字节为单位）为0时，做一些操作
return View();
}
else
{
//文件大小不为0
HttpPostedFileBase files = Request.Files[0];
//保存成自己的文件全路径,newfile就是你上传后保存的文件,
string newFile = DateTime.Now.ToString("yyyyMMddHHmmss") ;
Access_token model = new Access_token();
model = pub.Check_Token();
string type = "image";
string url = string.Format("http://file.api.weixin.qq.com/cgi-bin/media/upload?access_token={0}&type={1}", model.access_token, type.ToString());
string path = "D://项目//个人//Senparc.Weixin.MP.Sample//Senparc.Weixin.MP.Sample//image//" + files.FileName;
//服务器上的UpLoadFile文件夹必须有读写权限
files.SaveAs(path);
string filename = System.Web.HttpContext.Current.Server.MapPath("/image/" + files.FileName);
string json = HttpUploadFile(url, filename);
JObject jb = (JObject)JsonConvert.DeserializeObject(json);//这里就能知道返回正确的消息了下面是个人的逻辑我就没写
..........................................
}
return Content("成功");
}
public static string HttpUploadFile(string url, string path)//这个方法是两个URL第一个url是条到微信的，第二个是本地图片路径
{
// 设置参数
HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;
CookieContainer cookieContainer = new CookieContainer();
request.CookieContainer = cookieContainer;
request.AllowAutoRedirect = true;
request.Method = "POST";
string boundary = DateTime.Now.Ticks.ToString("X"); // 随机分隔线
request.ContentType = "multipart/form-data;charset=utf-8;boundary=" + boundary;
byte[] itemBoundaryBytes = Encoding.UTF8.GetBytes("
--" + boundary + "
");
byte[] endBoundaryBytes = Encoding.UTF8.GetBytes("
--" + boundary + "--
");
int pos = path.LastIndexOf("\");
string fileName = path.Substring(pos + 1);
//请求头部信息
StringBuilder sbHeader = new StringBuilder(string.Format("Content-Disposition:form-data;name="file";filename="{0}"
Content-Type:application/octet-stream
", fileName));
byte[] postHeaderBytes = Encoding.UTF8.GetBytes(sbHeader.ToString());
FileStream fs = new FileStream(path, FileMode.Open, FileAccess.Read);
byte[] bArr = new byte[fs.Length];
fs.Read(bArr, 0, bArr.Length);
fs.Close();
Stream postStream = request.GetRequestStream();
postStream.Write(itemBoundaryBytes, 0, itemBoundaryBytes.Length);
postStream.Write(postHeaderBytes, 0, postHeaderBytes.Length);
postStream.Write(bArr, 0, bArr.Length);
postStream.Write(endBoundaryBytes, 0, endBoundaryBytes.Length);
postStream.Close();
//发送请求并获取相应回应数据
HttpWebResponse response = request.GetResponse() as HttpWebResponse;
//直到request.GetResponse()程序才开始向目标网页发送Post请求
Stream instream = response.GetResponseStream();
StreamReader sr = new StreamReader(instream, Encoding.UTF8);
//返回结果网页（html）代码
string content = sr.ReadToEnd();
return content;
}
4、前台的这句话@using (Html.BeginForm("Upload", "Source", FormMethod.Post, new { enctype = "multipart/form-data" }))中
new { enctype = "multipart/form-data" }是必须要的，
这样就会访问到Upload这个方法接下来就两个方法的执行了那么就看第3步骤了