在ASP.NET中实现上传图片，并按比例生成缩略图

击水之石

在ASP.NET中实现上传图片，并按比例生成缩略图
[ 2007-1-23 16:43:00 | By: 玩物丧志 ]

private void btnUploadPicture_Click(object sender, System.EventArgs e)
{
    //检查上传文件的格式是否有效
    if(this.UploadFile.PostedFile.ContentType.ToLower().IndexOf("image") < 0)
    {
     Response.Write("上传图片格式无效！");
     return;
    }

    //生成原图
    Byte[] oFileByte = new byte[this.UploadFile.PostedFile.ContentLength];
    System.IO.Stream oStream = this.UploadFile.PostedFile.InputStream;
    System.Drawing.Image oImage = System.Drawing.Image.FromStream(oStream);

    int oWidth = oImage.Width; //原图宽度
    int oHeight = oImage.Height; //原图高度
    int tWidth = 100; //设置缩略图初始宽度
    int tHeight = 100; //设置缩略图初始高度

    //按比例计算出缩略图的宽度和高度
    if(oWidth >= oHeight)
    {
     tHeight = (int)Math.Floor(Convert.ToDouble(oHeight) * (Convert.ToDouble(tWidth) / Convert.ToDouble(oWidth)));
    }
    else
    {
     tWidth = (int)Math.Floor(Convert.ToDouble(oWidth) * (Convert.ToDouble(tHeight) / Convert.ToDouble(oHeight)));
    }

    //生成缩略原图
    Bitmap tImage = new Bitmap(tWidth,tHeight);
    Graphics g = Graphics.FromImage(tImage);
    g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High; //设置高质量插值法
    g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;//设置高质量,低速度呈现平滑程度
    g.Clear(Color.Transparent); //清空画布并以透明背景色填充
    g.DrawImage(oImage,new Rectangle(0,0,tWidth,tHeight),new Rectangle(0,0,oWidth,oHeight),GraphicsUnit.Pixel);

    string oFullName = Server.MapPath(".") + "/" + "o" + DateTime.Now.ToShortDateString().Replace("-","") + DateTime.Now.Hour.ToString() + DateTime.Now.Minute.ToString() + DateTime.Now.Second.ToString() + DateTime.Now.Millisecond.ToString() + ".jpg"; //保存原图的物理路径
    string tFullName = Server.MapPath(".") + "/" + "t" + DateTime.Now.ToShortDateString().Replace("-","") + DateTime.Now.Hour.ToString() + DateTime.Now.Minute.ToString() + DateTime.Now.Second.ToString() + DateTime.Now.Millisecond.ToString() + ".jpg"; //保存缩略图的物理路径

    try
    {
     //以JPG格式保存图片
     oImage.Save(oFullName,System.Drawing.Imaging.ImageFormat.Jpeg);
     tImage.Save(tFullName,System.Drawing.Imaging.ImageFormat.Jpeg);
    }
    catch(Exception ex)
    {
     throw ex;
    }
    finally
    {
     //释放资源
     oImage.Dispose();
     g.Dispose();
     tImage.Dispose();
    }
}

彬彬有礼

一楼的位置好啊..我考，这是一种文明，我指　的是回帖。