转至：http://www.cnblogs.com/fonour/p/ajaxFileUpload.html
0、下载 http://files.cnblogs.com/files/fonour/ajaxfileupload.js
1、引用ajaxfileupload.js
<script src="../../Content/js/jquery-2.1.4.min.js"></script>
<script src="../../Content/js/ajaxfileupload.js"></script>
2、页面添加类型为file的input标签
<input type="file" id="filePicture" name="filePicture" accept=".jpg,.jpeg,.png,.bmp" onchange="filePictureChange()" />
3、添加了onchange事件，在选择文件后立即上传文件，onchange时间定义如下
var filePictureChange = function(){
$.ajaxFileUpload({
type: "post", //请求类型：post或get,当要使用data提交自定义参数时一定要设置为post
url: "/Shared/Upload", //文件上传的服务器端请求地址
secureuri: false, //是否启用安全提交，一般默认为false就行，不用特殊处理
fileElementId: "filePicture", //文件上传控件的id <input type="file" id="filePicture" name="filePicture" accept=".jpg,.jpeg,.png,.bmp" onchange="filePictureChange()" />
dataType: "json", //返回值类型，一般设置为json，还支持html\xml\script类型
data: { "id": "", "name": "test" }, //用于post请求提交自定义参数
success: function (data, status) { //服务器成功响应处理函数
},
error: function (data, status, e) { //服务器响应失败处理函数
}
});
}
4、后台控制器方法
/// <summary>
/// 附件上传
/// </summary>
/// <returns></returns>
[HttpPost]
public ActionResult AjaxUpload()
{
HttpFileCollection files = System.Web.HttpContext.Current.Request.Files;
if (files.Count == ) return Json("Faild", JsonRequestBehavior.AllowGet);
MD5 md5Hasher = new MD5CryptoServiceProvider();
/*计算指定Stream对象的哈希值*/
byte[] arrbytHashValue = md5Hasher.ComputeHash(files[].InputStream);
/*由以连字符分隔的十六进制对构成的String，其中每一对表示value中对应的元素；例如“F-2C-4A”*/
string strHashData = System.BitConverter.ToString(arrbytHashValue).Replace("-", "");
string FileEextension = Path.GetExtension(files[].FileName);
string uploadDate = DateTime.Now.ToString("yyyyMMdd");
string virtualPath = string.Format("/upload/{0}/{1}{2}", uploadDate, strHashData, FileEextension);
string fullFileName = Server.MapPath(virtualPath);
//创建文件夹，保存文件
string path = Path.GetDirectoryName(fullFileName);
Directory.CreateDirectory(path);
if (!System.IO.File.Exists(fullFileName))
{
files[].SaveAs(fullFileName);
}
string fileName = files[].FileName.Substring(files[].FileName.LastIndexOf("\\") + , files[].FileName.Length - files[].FileName.LastIndexOf("\\") - );
string fileSize = GetFileSize(files[].ContentLength);
return Json(new { FileName = fileName, FilePath = virtualPath, FileSize = fileSize }, "text/html", JsonRequestBehavior.AllowGet);
}
/// <summary>
/// 获取文件大小
/// </summary>
/// <param name="bytes"></param>
/// <returns></returns>
private string GetFileSize(long bytes)
{
long kblength = ;
long mbLength = * ;
if (bytes < kblength)
return bytes.ToString() + "B";
if (bytes < mbLength)
return decimal.Round(decimal.Divide(bytes, kblength), ).ToString() + "KB";
else
return decimal.Round(decimal.Divide(bytes, mbLength), ).ToString() + "MB";
}