/// <summary>
/// 上传生成缩略图
/// </summary>
/// <param name="FileUpload1">上传文件控件</param>
/// <param name="uploadFile">上传文件夹如"file/"</param>
/// <param name="ytName">保存的原图片名 不带后缀</param>
/// <param name="slName">保存的缩略图名 不带后缀</param>
/// <returns></returns>
public string MakeThumbnail(FileUpload FileUpload1, string uploadFile, string ytName, string slName, int width, int height)
{
//FileUpload1图片上传控件
if (FileUpload1.HasFile)
{
//要考虑文件大小
string filetype = FileUpload1.PostedFile.ContentType.ToLower();
if (filetype == "image/gif" || filetype == "image/png" || filetype == "image/jpeg")
{
try
{
string myTime;
string date_folder;
string gpic;
// myTime = DateTime.Now.ToString("yyyyMMddHHmmss") + DateTime.Now.Millisecond.ToString("000");
string gfile = FileUpload1.PostedFile.FileName;
string pic_path = System.Web.HttpContext.Current.Server.MapPath(uploadFile); // 上传文件夹
//判断上传文件夹是否存在，不存在则创建
DirectoryInfo myFolder = new DirectoryInfo(pic_path);
if (!myFolder.Exists)
{ myFolder.Create(); }
FileInfo MyFile = new FileInfo(gfile);
gpic = ytName + MyFile.Extension;//原图名
string save_filePath = System.Web.HttpContext.Current.Server.MapPath(uploadFile + gpic);
FileUpload1.SaveAs(save_filePath); //上传原图
string gp = System.Web.HttpContext.Current.Server.MapPath(uploadFile + gpic);
string gn = System.Web.HttpContext.Current.Server.MapPath(uploadFile+slName + MyFile.Extension);//缩略图名
Stream sm = new FileStream(gp, FileMode.Open);
System.Drawing.Image img = System.Drawing.Image.FromStream(sm);
int towidth = width;//缩略图宽度
int toheight = height;//缩略图高度
int ow = img.Width;
int oh = img.Height;
if (ow > oh)
{
toheight = img.Height * towidth / img.Width;
}
else
{
towidth = img.Width * toheight / img.Height;
}
img = img.GetThumbnailImage(towidth, toheight, null, IntPtr.Zero);
img.Save(gn, System.Drawing.Imaging.ImageFormat.Jpeg);//上传缩略图
img.Dispose();
sm.Close();
sm.Dispose();
return "上传成功";
}
catch
{
return "错误!";
}
}
else
{
return "类型不符";
}
}
else
{
return "请选择文件!";
}
}
------------------test---------------------------
protected void Button1_Click(object sender, EventArgs e)
{
MakeThumbnail(FileUpload1, "file/", "wjl", "wjls", 118, 118);
FileInfo MyFile = new FileInfo(FileUpload1.PostedFile.FileName);
//删除原图
FileInfo delPic = new FileInfo(Server.MapPath("file/wjl"+MyFile.Extension));
if (delPic.Exists)
{ delPic.Delete(); }
Image1.ImageUrl = "file/wjls"+MyFile.Extension;
}
摘自 http://hi.baidu.com/wenjunlin/blog/item/ef12c1d6bc4b6f2307088bbf.html