Asp.Net上传图片同时生成高清晰缩略图

 /// <summary>
 /// asp.net上传图片并生成缩略图
 /// </summary>
 /// <param name="upImage">HtmlInputFile控件</param>
 /// <param name="sSavePath">保存的路径,些为相对服务器路径的下的文件夹</param>
 /// <param name="sThumbExtension">缩略图的thumb</param>
 /// <param name="intThumbWidth">生成缩略图的宽度</param>
 /// <param name="intThumbHeight">生成缩略图的高度</param>
 /// <returns>缩略图名称</returns>
 public string UpLoadImage(HtmlInputFile upImage, string sSavePath, string sThumbExtension, int intThumbWidth, int intThumbHeight)
 {
 string sThumbFile = "";
 string sFilename = ""; 
 if (upImage.PostedFile != null)
 {
 HttpPostedFile myFile = upImage.PostedFile;
 int nFileLen = myFile.ContentLength;
 if (nFileLen == 0)
 return "没有选择上传图片"; 
 //获取upImage选择文件的扩展名
 string extendName = System.IO.Path.GetExtension(myFile.FileName).ToLower();
 //判断是否为图片格式
 if (extendName != ".jpg" && extendName != ".jpge" && extendName != ".gif" && extendName != ".bmp" && extendName != ".png")
 return "图片格式不正确";
 
 byte[] myData = new Byte[nFileLen];
 myFile.InputStream.Read(myData, 0, nFileLen);
 sFilename = System.IO.Path.GetFileName(myFile.FileName);
 int file_append = 0;
 //检查当前文件夹下是否有同名图片,有则在文件名+1
 while (System.IO.File.Exists(System.Web.HttpContext.Current.Server.MapPath(sSavePath + sFilename)))
 {
 file_append++;
 sFilename = System.IO.Path.GetFileNameWithoutExtension(myFile.FileName)
 + file_append.ToString() + extendName;
 }
 System.IO.FileStream newFile
 = new System.IO.FileStream(System.Web.HttpContext.Current.Server.MapPath(sSavePath + sFilename),
 System.IO.FileMode.Create, System.IO.FileAccess.Write);
 newFile.Write(myData, 0, myData.Length);
 newFile.Close();
 //以上为上传原图
 try
 {
 //原图加载
 using (System.Drawing.Image sourceImage = System.Drawing.Image.FromFile(System.Web.HttpContext.Current.Server.MapPath(sSavePath + sFilename)))
 {
 //原图宽度和高度
 int width = sourceImage.Width;
 int height = sourceImage.Height;
 int smallWidth;
 int smallHeight;
 //获取第一张绘制图的大小,(比较 原图的宽/缩略图的宽 和 原图的高/缩略图的高)
 if (((decimal)width) / height <= ((decimal)intThumbWidth) / intThumbHeight)
 {
 smallWidth = intThumbWidth;
 smallHeight = intThumbWidth * height / width;
 }
 else
 {
 smallWidth = intThumbHeight * width / height;
 smallHeight = intThumbHeight;
 }
 //判断缩略图在当前文件夹下是否同名称文件存在
 file_append = 0;
 sThumbFile = sThumbExtension + System.IO.Path.GetFileNameWithoutExtension(myFile.FileName) + extendName;
 while (System.IO.File.Exists(System.Web.HttpContext.Current.Server.MapPath(sSavePath + sThumbFile)))
 {
 file_append++;
 sThumbFile = sThumbExtension + System.IO.Path.GetFileNameWithoutExtension(myFile.FileName) +
 file_append.ToString() + extendName;
 }
 //缩略图保存的绝对路径
 string smallImagePath = System.Web.HttpContext.Current.Server.MapPath(sSavePath) + sThumbFile;
 //新建一个图板,以最小等比例压缩大小绘制原图
 using (System.Drawing.Image bitmap = new System.Drawing.Bitmap(smallWidth, smallHeight))
 {
 //绘制中间图
 using (System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap))
 {
 //高清,平滑
 g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
 g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
 g.Clear(Color.Black);
 g.DrawImage(
 sourceImage,
 new System.Drawing.Rectangle(0, 0, smallWidth, smallHeight),
 new System.Drawing.Rectangle(0, 0, width, height),
 System.Drawing.GraphicsUnit.Pixel
 );
 }
 //新建一个图板,以缩略图大小绘制中间图
 using (System.Drawing.Image bitmap1 = new System.Drawing.Bitmap(intThumbWidth, intThumbHeight))
 {
 //绘制缩略图 http://www.cnblogs.com/sosoft/
 using (System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap1))
 {
 //高清,平滑
 g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
 g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
 g.Clear(Color.Black);
 int lwidth = (smallWidth - intThumbWidth) / 2;
 int bheight = (smallHeight - intThumbHeight) / 2;
 g.DrawImage(bitmap, new Rectangle(0, 0, intThumbWidth, intThumbHeight), lwidth, bheight, intThumbWidth, intThumbHeight, GraphicsUnit.Pixel);
 g.Dispose();
 bitmap1.Save(smallImagePath, System.Drawing.Imaging.ImageFormat.Jpeg);
 }
 }
 }
 }
 }
 catch
 {
 //出错则删除
 System.IO.File.Delete(System.Web.HttpContext.Current.Server.MapPath(sSavePath + sFilename));
 return "图片格式不正确";
 }
 //返回缩略图名称
 return sThumbFile;
 }
 return "没有选择图片";
 }

 <%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default2.aspx.cs" Inherits="Default2" %>
 <!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>图片上传-柯乐义</title>
 </head>
 <body>
 <form id="form1" runat="server">
 <div> 
 <input id="File1" runat="server" type="file" /></div><asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="Button" />
 </form>
 </body>
 </html>

 protected void Button1_Click(object sender, EventArgs e)
 {
 string a = this.UpLoadImage(this.File1, "UpLoad/", "thumb_", 118, 118); 
 }