如何使用asp.net C＃调整图像大小而不保存图像

Question

I use this code to re-size images, but my problem is that I have to save the original picture then re-size that! How can I re-size a picture without saving it? I want to re-size the picture first and then save it.

 FileUpload1.SaveAs("saveOriginalFileFirstHere");
 string thumbpath = "where resized pic should be saved";
 MakeThumbnails.makethumb("saveOriginalFileFirstpath", thumbpath);


 public static void makethumb(string savedpath, string thumbpath)

 {
   int resizeToWidth = 200;
   int resizeToHeight = 200;
   Graphics graphic;
   //Image photo; // your uploaded image
   Image photo = new Bitmap(savedpath);
   //  Image photo = new  j
   Bitmap bmp = new Bitmap(resizeToWidth, resizeToHeight);
   graphic = Graphics.FromImage(bmp);
   graphic.InterpolationMode = InterpolationMode.Default;
   graphic.SmoothingMode = SmoothingMode.Default;
   graphic.PixelOffsetMode = PixelOffsetMode.Default;
   graphic.CompositingQuality = CompositingQuality.Default;
   graphic.DrawImage(photo, 0, 0, resizeToWidth, resizeToHeight);
   bmp.Save(thumbpath);
 }

Answer 1

Use the InputStream property of the uploaded file instead:

I have modified your code to do so:

EDIT: You really should dispose of your IDisposables, such as your bitmaps and the stream, to avoid memory leakage. I have updated my code, so it will properly dispose these resources after it's done with them.

 string thumbpath = "where resized pic should be saved";
 MakeThumbnails.makethumb(FileUpload1.InputStream, thumbpath);


 public static void makethumb(Stream stream, string thumbpath)
 {
    int resizeToWidth = 200;
    int resizeToHeight = 200;

    using (stream)
    using (Image photo = new Bitmap(stream))
    using (Bitmap bmp = new Bitmap(resizeToWidth, resizeToHeight))
    using (Graphics graphic = Graphics.FromImage(bmp))
    {
        graphic.InterpolationMode = InterpolationMode.Default;
        graphic.SmoothingMode = SmoothingMode.Default;
        graphic.PixelOffsetMode = PixelOffsetMode.Default;
        graphic.CompositingQuality = CompositingQuality.Default;
        graphic.DrawImage(photo, 0, 0, resizeToWidth, resizeToHeight);
        bmp.Save(thumbpath);
    }
 }

This should work the way you want it to, if it doesn't, or if anything is unclear, please let me know.