html前台：
<body>
<form id="form1" enctype="multipart/form-data" method="post" action="Handler1.ashx">
<input type="file" name="myfile" value="123" /><br/>
<input type="submit" name="file" />
</form>
</body>
注意：enctype="multipart/form-data"设置后才能够提交服务器（一般处理程序） method="post"的设置
一般处理程序ashx：
public class Handler1 : IHttpHandler
{
public void ProcessRequest(HttpContext context)
{
context.Response.ContentType = "text/plain";
//接收客户端上传文件
HttpFileCollection fct = context.Request.Files;
if (fct.Count > 0)
{
HttpPostedFile hpf = fct[0];
//获取文件扩展名
string ext = System.IO.Path.GetExtension(hpf.FileName);
Random red = new Random();
string date = DateTime.Now.ToString("yyMMddhhmmss");
string filename = context.Request.MapPath("~/Image/" + date + red.Next(1000, 10000) + ext);
//string Filename = System.IO.Path.GetFileName(hpf.FileName);
//保存文件
hpf.SaveAs(filename);
context.Response.Write("上传文件成功");
}
else
{
context.Response.Write("请上传文件");
}
}
public bool IsReusable
{
get
{
return false;
}
}
}
这个不能防止空文件上传和格式控制：（图片格式可也用js代码判断，基于给户交互效果）
修改后：
public void ProcessRequest(HttpContext context) { context.Response.ContentType = "text/plain"; //接收客户端上传文件 HttpFileCollection fct = context.Request.Files; if (fct.Count > 0) { HttpPostedFile hpf = fct[0]; if (hpf.ContentLength > 0)//防止用户空文件上传 { if (hpf.ContentType == "image/jpeg" || hpf.ContentType == "image/png") { //获取文件扩展名 string ext = System.IO.Path.GetExtension(hpf.FileName); Random red = new Random(); string date = DateTime.Now.ToString("yyMMddhhmmss"); string filename = context.Request.MapPath("~/Image/" + date + red.Next(1000, 10000) + ext); //string Filename = System.IO.Path.GetFileName(hpf.FileName); //保存文件 hpf.SaveAs(filename); context.Response.Write("上传文件成功"); } else { context.Response.Write("禁止上传！"); } } else { context.Response.Write("上传失败。"); } } else { context.Response.Write("请上传文件"); } }
js控制：
<script type="text/javascript">
function checkext() {
var file = document.getElementById("file").value;
var ext=file.substr(file.lastIndexOf(".")+1);
if (ext.toLowerCase() == "jpg" || ext.toLowerCase() == "png") {
return true;
}
else {
alert("禁止上传");
return false;
}
}
</script>
控制文件上传大小：
在web.confige中<system.web>节点下配置：
<httpRuntime maxRequestLength="1024000"/>