前台页面：WebForm1.aspx
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="WebApplication1.WebForm1" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>无标题页</title>
</head>
<body>
<form method="post" encType="multipart/form-data" runat="server">
<FONT >
<TABLE
cellSpacing="1" cellPadding="1" width="568" >
<TR>
<TD ><asp:label runat="server">要上传的图片</asp:label></TD>
<TD ><INPUT type="file" name="File1" runat="server"></TD>
<TD ><asp:button runat="server" Text="上传并生成缩略图"></asp:button></TD>
</TR>
<TR>
<TD ><asp:label runat="server">原图片</asp:label></TD>
<TD align="center" colSpan="2"><asp:image runat="server"></asp:image></TD>
</TR>
<TR>
<TD><asp:label runat="server">缩略图</asp:label></TD>
<TD align="center" colSpan="2"><asp:image runat="server"></asp:image></TD>
</TR>
</TABLE>
</FONT>
</form>
</body>
</html>
后台代码：WebForm1.aspx.cs
using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
namespace WebApplication1
{
public partial class WebForm1 : System.Web.UI.Page
{
//定义image类的对象
System.Drawing.Image image, newimage;
//图片路径
protected string imagePath;
//图片类型
protected string imageType;
//图片名称
protected string imageName;
//提供一个回调方法,用于确定Image对象在执行生成缩略图操作时何时提前取消执行
//如果此方法确定 GetThumbnailImage 方法应提前停止执行，则返回 true；否则返回 false
System.Drawing.Image.GetThumbnailImageAbort callb = null;
private void Page_Load(object sender, System.EventArgs e)
{
this.btnUp.Click += new System.EventHandler(this.btnUp_Click);
this.Load += new System.EventHandler(this.Page_Load);
// 在此处放置用户代码以初始化页面
}
private void btnUp_Click(object sender, System.EventArgs e)
{
string mPath;
if ("" != upImage.PostedFile.FileName)
{
imagePath = upImage.PostedFile.FileName;
//取得图片类型
imageType = imagePath.Substring(imagePath.LastIndexOf(".") + 1);
//取得图片名称
imageName = imagePath.Substring(imagePath.LastIndexOf("\\") + 1);
//判断是否是JPG或者GIF图片,这里只是举个例子,并不一定必须是这两种图片
if ("jpg" != imageType && "gif" != imageType)
{
Response.Write("<script language='javascript'> alert('对不起！请您选择jpg或者gif格式的图片！');</script>");
return;
}
else
{
try
{
//建立虚拟路径
mPath = Server.MapPath("upFile");
//保存到虚拟路径
upImage.PostedFile.SaveAs(mPath + "\\" + imageName);
//显示原图
imageSource.ImageUrl = "upFile/" + imageName;
//为上传的图片建立引用
image = System.Drawing.Image.FromFile(mPath + "\\" + imageName);
//生成缩略图
newimage = image.GetThumbnailImage(100, 100, callb, new System.IntPtr());
//把缩略图保存到指定的虚拟路径
newimage.Save(Server.MapPath("upFile") + "\\small" + imageName);
//释放image对象占用的资源
image.Dispose();
//释放newimage对象的资源
newimage.Dispose();
//显示缩略图
imageSmall.ImageUrl = "upFile/" + "small" + imageName;
Response.Write("上传成功!");
}
catch
{
Response.Write("上传成功!");
}
}
}
}
}
}