alpha transparency on images/icons

[John Morey]

Im currently working on a Windows Form application in C# under .Net , the
graphic designer I intend to work with asked me if I would be able to
accomidate PNG style alpha transparency in images and icons within the
application , I guess this would depend on whether or not this is upported
within the .Net framework , would this need any extra libraries or code, or
do standard Windows.Forms image classes support this?

 

[Jeroen Smits]

..NET supports PNG images with alpha images. I'm using them myself.

However when you are using the Windows.Forms.ImageList class - which
controls like ListView and TreeView use for there icons - it's a little more
complex. In this case alpha images are only supported on Windows XP/2003
when using a manifest for activation v6 of the common controls dll.

On W2K I could only added 24bit images to the ImageList, because 32bit
images gave black borders. And on W9x systems I even needed to convert them
to 256bit or I got an exception.

But on controls that simply use a System.Drawing.Image object for the image,
32bit alpha images are supported.