该实现是参看http://www.cnblogs.com/wutao/archive/2010/01/28/1658496.html里的批量上传文件，对其进行了修改；整个过程是选择一张图片，然后对这张图片进行预览，当图片过大时不能预览(在uploadPreview.js文件里有限制大小)，最后点击上传则进行上传；请先下载：jquery；导入到.html文件里
<script language="javascript" src="../js/jquery.js"></script>
<script language="javascript" src="../js/uploadPreview.js"></script>
然后写：
<script language="javascript">
$(document).ready(function() {
//图片预览
$("#imgfile").uploadPreview({ imgDiv: "#imgDiv", imgType: ["bmp", "gif", "png", "jpg"], max 250, maxheight: 250 });
//上传图片
$("#btnUpload").click(function() {
$.post("exec/UploadFile.ashx", { upfile: getPath($("#imgfile")) }, function(json) {
//json.result为upload.ashx文件返回的值
alert(json.result);
},"json");
});
});
</script>
<body>
<input type="file" id="imgfile" />
<input type="button" id="btnUpload" value="上传图片" />
<div id="imgDiv" runat="server"></div> //显示预览图片
</body>
接下来：
在项目里添加一个一般处理程序：Handler1.ashx，把其改名为：UploadFile.ashx，在此应引用Newtonsoft.Json.dll，下载：/Files/KimhillZhang/json.rar
代码如下：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Services;
using System.IO;
using System.Text;
using System.Net;
using Newtonsoft.Json;
using Newtonsoft.Json.Converters;
namespace TianzhiguWebSite.Web.admincp.exec
{
/// <summary>
/// $codebehindclassname$ 的摘要说明
/// </summary>
[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
public class UploadFile : IHttpHandler
{
public void ProcessRequest(HttpContext context)
{
//源图片路径
string _fileNamePath = "";
try
{
_fileNamePath = context.Request["upfile"].ToString();
string _savedFileResult = uploadFile(_fileNamePath); //开始上传
//把编译成的json格式返回到前台
context.Response.Write(uploadFileResult(_savedFileResult));
}
catch
{
}
}
private string uploadFile(string filenamePath)
{
//图片格式
string fileNameExit = filenamePath.Substring(filenamePath.IndexOf('.')).ToLower();
if (!checkfileExit(fileNameExit))
{
return "图片格式不正确";
}
//保存路径
string toFilePath = "UploadFiles/";
//物理完整路径
string toFileFullPath = HttpContext.Current.Server.MapPath(toFilePath);
//检查是否有该路径，没有就创建
if (!Directory.Exists(toFileFullPath))
{
Directory.CreateDirectory(toFileFullPath);
}
//生成将要保存的随机文件名
string toFileName = getFileName();
//将要保存的完整路径
string saveFile = toFileFullPath + toFileName + fileNameExit;
//创建WebClient实例
WebClient myWebClient = new WebClient();
//设定window网络安全认证
myWebClient.Credentials = CredentialCache.DefaultCredentials;
//要上传的文件
FileStream fs = new FileStream(filenamePath, FileMode.Open, FileAccess.Read);
BinaryReader br = new BinaryReader(fs);
//使用UploadFile方法可以用下面的格式
myWebClient.UploadFile(saveFile, filenamePath);
return "图片保存成功";
}
/// <summary>
/// 检查图片格式
/// </summary>
/// <param name="_fileExit">文件后缀名</param>
/// <returns></returns>
private bool checkfileExit(string _fileExit)
{
string[] allowExit = new string[] { ".gif", ".jpg", ".png" };//判断文件类型
for (int i = 0; i < allowExit.Length; i++)
{
if (allowExit[i] == _fileExit)
{
//符合文件类型则返回true;
return true;
}
}
return false;
}
/// <summary>
/// 得到随机的文件名
/// </summary>
/// <returns></returns>
public static string getFileName()
{
Random rd = new Random();
StringBuilder serial = new StringBuilder();
serial.Append(DateTime.Now.ToString("yyMMddHHmmssff"));
serial.Append(rd.Next(0, 9999).ToString());
return serial.ToString();
}
public bool IsReusable
{
get
{
return false;
}
}
//把返回值编译成json格式
public string uploadFileResult(string result)
{
StringBuilder sb = new StringBuilder();
StringWriter sw = new StringWriter(sb);
using (JsonWriter jswriter = new JsonTextWriter(sw))
{
jswriter.Formatting = Formatting.Indented;
jswriter.WriteStartObject();
jswriter.WritePropertyName("result");
jswriter.WriteValue(result);
jswriter.WriteEnd();
}
return sb.ToString();
}
}
}