让ASP.NET的FileUpload控件支持浏览自动上传功能(转载)

FileUpload控件默认不支持服务端的ONCHANGE事件，此时用一种变通的方法借用客户端的onchange事件，调用__doPostBack方法来用LinkButton的OnClick事件模拟一个事件触发的过程，具体代码如下：

客户端：

<asp:FileUpload ID="fuPhoto" onchange="javascript:__doPostBack('lbUploadPhoto','')" runat="server" ToolTip="选择图片" /> 
<asp:LinkButton ID="lbUploadPhoto" runat="server" OnClick="lbUploadPhoto_Click"></asp:LinkButton>

后台代码：

1.//自动上传事件 
2.       protected void lbUploadPhoto_Click(object sender, EventArgs e) 
3.       { 
4.           fileUpload(); 
5.       } 
6.       //从控件上传文件 
7.       public void fileUpload() 
8.       { 
9.           if (fuPhoto.PostedFile != null && fuPhoto.PostedFile.ContentLength > 0) 
10.           { 
11.               string ext = System.IO.Path.GetExtension(fuPhoto.PostedFile.FileName).ToLower(); 
12.               if (ext != ".jpg" && ext != ".jepg" && ext != ".bmp" && ext != ".gif") 
13.               { 
14.                   return; 
15.               } 
16.               string filename = "Image_" + DateTime.Now.ToString("yyyyMMddHHmmss") + ext; 
17.               string path = "./UploadPhoto/" + filename; 
18.               fuPhoto.PostedFile.SaveAs(Server.MapPath(path)); 
19.               Response.Redirect("ImageCut.aspx?Picurl=" + Server.UrlEncode(path)); 
20.           } 
21.           else 
22.           { 
23.               //do some thing; 
24.           } 
25.       }