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);   }