Mark correct sign on file or folder icon at bottom left after upload same as Dropbox does

Question

Assuming that you know about drop box(no problem if you don't know).

In my desktop application there is an upload functionality. I want to mark correct sign on file icon at bottom left after upload.(same as Dropbox does).

How can I do that? What's that trick?

Answer 1

DropBox is a shell extension, so it uses the OS icons and overlay them.

In your case, if it's a desktop application you can overlay your icons using something similar to this:

    private static object mOverlayLock = new object();
    public static Image GetOverlayedImage(Image baseImage, Image overlay)
    {
        Image im = null;

        lock (mOverlayLock)
        {
            try
            {
                im = baseImage.Clone() as Image;

                Graphics g = Graphics.FromImage(im);
                g.DrawImage(overlay, 0, 0, im.Width, im.Height);
                g.Dispose();
            }
            catch
            {
                // LOG EXCEPTION!!
            }
        }

        return im;
    }

This is a basic example. You can also play with the overlay position, (topleft, middleleft ...), that requires a little bit more programming.

Then, from your application you can call this method to get the result image. For example

...
Image folderIcon = GetFolderIcon();
Image upToDateOverlay = GetUpToDateOverlay();
Image folderUptoDate = GetOlverlayedImage(folderIcon, upToDateOverlay);
// Then assign this image to your control item (treelistnode, listViewnode, whatever)