c# - Black image when saving PNG from clipboard -

i trying save png image has been copied clipboard, either turning out solid black, or black around areas should transparent.

here code using capture , save image

var clipboardimage = (interopbitmap)clipboard.getimage();  image.saveimage(clipboardimage, path.combine(config.app.applicationdataimagespath, string.format("{0}.{1}", imageid, "png")));  public static void saveimage(bitmapsource bitmapimage, string filename) {     using (var filestream = new filestream(filename, filemode.create))     {         var pngbitmapencoder = new pngbitmapencoder();         pngbitmapencoder.frames.add(bitmapframe.create(bitmapimage));         pngbitmapencoder.save(filestream);         filestream.close();         filestream.dispose();     }            } 

does have ideas why won't persrve alpha channels of png?

thanks

dan

edit: should of mentioned black images happening when copying image internet explorer 9. works when copying image either chrome or firefox. workarounds ie9 issue?

what happens if this:

clipboard.getimage().save ("xxx.png", system.drawing.imaging.imageformat.png); 

edit - wpf try this:

public static void saveclipboardimagetofile(string filepath) {     var image = clipboard.getimage();     using (var filestream = new filestream(filepath, filemode.create))     {         bitmapencoder encoder = new pngbitmapencoder();         encoder.frames.add(bitmapframe.create(image));         encoder.save(filestream);     } }