.NET图片上传类（支持任何大小的缩略图）直接调用 简单易理解

饮水思源：http://aiyuanwordcup.blog.163.com/blog/static/43926158200821004814394/

using System;using System.Web;using System.Drawing;using System.Threading; namespace Happy2006.Web.Utility{ /// <summary> /// FileUpload 的摘要说明。 /// 支持缩略图的图片上传类，若不传图片则无缩略图支持 /// path里可以用 / 表示分割，其他不支持 ;/ 会自动转换为 / /// </summary> public class FileUpload { public static System.Web.UI.Page objPage; private string m_strDestPath=""; private string m_strThumbDestPath=""; private int m_nThumbWidth=0; private int m_nThumbHeight=0; private long m_nMaxSize=0; private string m_strPreFixThumb=""; private static FileUpload m_objFileUpload; private static Object m_classLock=typeof(FileUpload); public static FileUpload getInstance(long nMaxFileSize,string strDestPath) { objPage= (System.Web.UI.Page)System.Web.HttpContext.Current.Handler ; if (null==objPage) { return null; } lock(m_classLock) { if(null==m_objFileUpload) { m_objFileUpload= new FileUpload( nMaxFileSize, strDestPath); } } return m_objFileUpload; } public static FileUpload getInstance( long nMaxFileSize, string strDestPath, string strThumbDestPath, int nThumbWidth, int nThumbHeight, string strPreFixThumb ) { objPage= (System.Web.UI.Page)System.Web.HttpContext.Current.Handler ; if (null==objPage) { return null; } lock(m_classLock) { if(null==m_objFileUpload) { m_objFileUpload= new FileUpload( nMaxFileSize, strDestPath, strThumbDestPath, nThumbWidth, nThumbHeight, strPreFixThumb ); } } return m_objFileUpload; } /// <summary> /// 路径格式转换为正确格式 /// </summary> /// <param name="strPath"></param> /// <returns></returns> private string PathFormat(string strPath) { string strReturn=strPath; if (strReturn.Length<=0) { return ""; } strReturn=strReturn.Replace("//","/"); if(strReturn.Substring(strReturn.Length-1)!= "/") { strReturn+="/"; } return strReturn; } /// <summary> /// /// </summary> /// <param name="nMaxFileSize">限制最大文件大小</param> /// <param name="strDestPath">文件上传目的路径</param> public FileUpload(long nMaxFileSize,string strDestPath) { m_strDestPath=PathFormat(strDestPath); m_nMaxSize=nMaxFileSize; } /// <summary> /// /// </summary> /// <param name="nMaxFileSize">单位KB</param> /// <param name="strDestPath"></param> /// <param name="strThumbDestPath">缩略图路径，为空串时，不生成缩略图</param> /// <param name="nThumbWidth"></param> /// <param name="nThumbHeight"></param> /// <param name="strPreFixThumb">缩略图前缀</param> public FileUpload(long nMaxFileSize, string strDestPath, string strThumbDestPath, int nThumbWidth, int nThumbHeight, string strPreFixThumb) { m_strDestPath=PathFormat(strDestPath); m_nMaxSize=nMaxFileSize; m_strThumbDestPath=PathFormat(strThumbDestPath); m_nThumbHeight=nThumbHeight; m_nThumbWidth=nThumbWidth; m_strPreFixThumb=strPreFixThumb; } public bool Upload(string strFileInputBoxID, string strDestFileName, out long nSrcFileSize, out string strSrcFileName, out string strSrcFileExt, out string strError) { nSrcFileSize=0; strSrcFileName=""; strSrcFileExt=""; strError=""; System.Web.UI.HtmlControls.HtmlInputFile objFileCtrl=(System.Web.UI.HtmlControls.HtmlInputFile)objPage.FindControl(strFileInputBoxID); if (null==objFileCtrl) { strError="没有页对象PAGE"; return false; } if (objFileCtrl.PostedFile.ContentLength==0) { strError="上传文件内容为空"; return false; } if(m_nMaxSize<=nSrcFileSize && m_nMaxSize>0) { strError="上传文件太大:"+m_nMaxSize.ToString() +" < "+ nSrcFileSize.ToString(); return false; } nSrcFileSize=(objFileCtrl.PostedFile.ContentLength/1024); strSrcFileName=objFileCtrl.PostedFile.FileName; strSrcFileExt=strSrcFileName.Substring(strSrcFileName.LastIndexOf(".")+1); try { objFileCtrl.PostedFile.SaveAs( m_strDestPath + strDestFileName + "."+ strSrcFileExt); } catch { strError="上传文件保存失败，请查看["+ m_strDestPath + "]路径是否可写"; return false; } int nSrcWidth,nSrcHeight; if (m_strThumbDestPath.Length>0) { if(false==GenerateThumb(m_strDestPath + strDestFileName + "."+ strSrcFileExt , m_strThumbDestPath, m_strPreFixThumb+"_" + strDestFileName + "."+ strSrcFileExt , m_nThumbWidth, m_nThumbHeight, out nSrcWidth, out nSrcHeight, out strError)) { return false; } } return true; } /// <summary> /// /// </summary> /// <param name="strSrcFilePathName">文件源</param> /// <param name="strDestPath">缩略图路径</param> /// <param name="strDestFileName">小图文件名包括扩展名</param> /// <param name="nDestWidth">为0时以nDestHeight为标准</param> /// <param name="nDestHeight">为0时以nDestWidth为标准</param> /// <param name="strError">返回的错误信息</param> /// <returns></returns> private bool GenerateThumb( string strSrcFilePathName, string strDestPath, string strDestFileName, int nDestWidth, int nDestHeight, out int nSrcWidth, out int nSrcHeight, out string strError) { //'生成缩略图 int nWidth=nDestWidth; int nHeight=nDestHeight; nSrcWidth=0; nSrcHeight=0; strError=""; System.Drawing.Image objImg=System.Drawing.Image.FromFile(strSrcFilePathName); if (null==objImg) { strError="原图不存在"; return false; } nSrcWidth=objImg.Width; nSrcHeight=objImg.Height; if (0==nWidth) { nWidth=Convert.ToInt32((Convert.ToDouble(nSrcWidth)/Convert.ToDouble(nSrcHeight)*nHeight)); } if (0==nHeight) { nHeight=Convert.ToInt32((Convert.ToDouble(nSrcHeight)/Convert.ToDouble(nSrcWidth)*nWidth)); } System.Drawing.Image objImgReturn; try { System.Drawing.Image.GetThumbnailImageAbort objFunctionCall=null; objImgReturn =objImg.GetThumbnailImage(nWidth,nHeight,objFunctionCall,new System.IntPtr()); objImgReturn.Save(strDestPath+strDestFileName); } catch { strError="生成缩略图失败！确认路径可写["+ strDestPath+strDestFileName +"],预生成大小为 "+ nWidth.ToString() +" x "+ nHeight.ToString()+" "+ nSrcHeight.ToString() + " " ; return false; } objImg.Dispose(); objImgReturn.Dispose(); return true; } }} 代码调用： Happy2006.Web.Utility.FileUpload objFile; if(!chkThumb.Checked)//是否支持缩略图生成 { objFile=Happy2006.Web.Utility.FileUpload.getInstance(0, Server.MapPath(@"/Happy2006WebTest/TestFile")); }else { objFile=Happy2006.Web.Utility.FileUpload.getInstance(0, Server.MapPath(@"/Happy2006WebTest/TestFile"), @"D:/Happy2006/TestFile",120,0,"thumb"); } string strFileName; long nFileSize; string strError; string strFileExt; if (null!=objFile) { objFile.Upload("fileupload","xxxx",out nFileSize,out strFileName,out strFileExt,out strError); Response.Write(strError); }