上传图片并生成略缩图

转自：http://blog.csdn.net/evenbing/archive/2007/09/19/1791163.aspx

参数说明FileBox:上传表单中的表单名SavePath:保存路径ThumbnailWidth:略缩图宽ThumbnailHeight:略缩图高FilePath:文件保存路径（输出参数）FileName:文件名称（输出参数）LastError:（输出错误）

public static bool UploadImages(System.Web.UI.HtmlControls.HtmlInputFile FileBox,string SavePath,Int32 ThumbnailWidth,Int32 ThumbnailHeight,out String FilePath,out String FileName,out string LastError){ DateTime datTime=System.DateTime.Now; String strTemp; string strFileName = FileBox.PostedFile.FileName; bool blnResult; LastError=""; System.Drawing.Image xImage; System.Drawing.Bitmap xBitmap; int PhotoHeight,PhotoWidth; string BasePath=System.Web.HttpContext.Current.Server.MapPath("../"); Rectangle NewPhoto; System.Drawing.Imaging.ImageFormat xObject; string Extension=""; FileName=""; FilePath="";

 try {  if(strFileName=="")  {   LastError="请点击浏览选择要上传的文件!";   return false;  }  if(Convert.ToDecimal(FileBox.PostedFile.ContentLength)<= 2000000 &&Convert.ToDecimal(FileBox.PostedFile.ContentLength)>1500)  {   //查看扩展名是否合法   Extension=Path.GetExtension(strFileName);   Extension=Extension.ToLower();   if(Extension==".gif" || Extension==".jpg" || Extension==".jpeg" || Extension==".bmp")   {    switch(Extension)    {     case ".gif":      xObject=System.Drawing.Imaging.ImageFormat.Gif;      break;     case ".bmp":      xObject=System.Drawing.Imaging.ImageFormat.Bmp;      break;     default:      xObject=System.Drawing.Imaging.ImageFormat.Jpeg;

      break;    }   }   else   {    LastError="上传的文件不是有效的图片文件，请上传格式为：.gif.jpg.bmp的文件！";    return false;   }   //-----------------------------   //生成保存的文件路径及文件名   //-----------------------------   strTemp = datTime.ToShortDateString().Replace( "-", "");   FileName = datTime.ToLongTimeString().Replace(":","")+ Extension;   FilePath = SavePath + strTemp + "/";   Friendlib.Function.CreateDirectory(BasePath + FilePath);   //保存大图   xImage=System.Drawing.Bitmap.FromStream(FileBox.PostedFile.InputStream);

   xImage.Save(BasePath+FilePath+FileName);   xImage.Dispose();   //-----------------------------   //开始生成缩略图   //-----------------------------   xBitmap=new Bitmap(BasePath+FilePath+FileName);//------------------

   PhotoHeight=xBitmap.Height;   PhotoWidth=xBitmap.Width;   // //判断图片的形状    if(Convert.ToDecimal(PhotoHeight)/Convert.ToDecimal(PhotoWidth)>Convert.ToDecimal(ThumbnailHeight)/Convert.ToDecimal(ThumbnailWidth))//高有余    {     PhotoHeight=Convert.ToInt16((Convert.ToDecimal(ThumbnailHeight)/Convert.ToDecimal(ThumbnailWidth))*Convert.ToDecimal(PhotoWidth));     NewPhoto=new Rectangle(0,0,PhotoWidth,PhotoHeight);    }    else if(Convert.ToDecimal(PhotoHeight)/Convert.ToDecimal(PhotoWidth)<Convert.ToDecimal(ThumbnailHeight)/Convert.ToDecimal(ThumbnailWidth))    {     PhotoWidth=Convert.ToInt16((Convert.ToDecimal(ThumbnailWidth)/Convert.ToDecimal(ThumbnailHeight))*Convert.ToDecimal(PhotoHeight));     NewPhoto=new      Rectangle(Convert.ToInt16((Convert.ToDecimal(xBitmap.Width)-Convert.ToDecimal(PhotoWidth))/2),0,PhotoWidth,PhotoHeight);    }    else    {     NewPhoto= newRectangle(0,0,PhotoWidth,PhotoHeight); < BR> }                    System.Drawing.Image myBitmap;     myBitmap=xBitmap.Clone(NewPhoto,System.Drawing.Imaging.PixelFormat.DontCare);     System.Drawing.Image.GetThumbnailImageAbort myCallback = new      System.Drawing.Image.GetThumbnailImageAbort(ThumbnailCallback);     System.Drawing.Image myThumbnail =      myBitmap.GetThumbnailImage(ThumbnailWidth,ThumbnailHeight, myCallback,      IntPtr.Zero); myThumbnail.Save(BasePath + FilePath +"s"+FileName,xObject);     myThumbnail.Dispose(); myBitmap.Dispose(); xBitmap.Dispose(); return true; }   else   {    blnResult=false; LastError="不能上传大于2M及小于1.5K的图片!";   }   }< BR>     catch (Exception ex)          {           throw new System.Exception((ex.Message + ("/r/n" + ex.StackTrace)));          }   return blnResult; }private static bool ThumbnailCallback() { return false; }