How should control images should be handled?

[~~~ .NET Ed ~~~]

This is something that has been nagging me over and over again and I think
there must be a better solution out there.

Some times (usually?) user controls and custom web controls need images such
as icons and other decorations in the form of images. The problem is... how
do you handle that in a way that everything is self-contained or at least
free form file system dependencies?

For example, the control needs a few icons and some background image for
part of the control. Is there a way to make it self-contained in the
Assembly? and if so, how can I extract/handle such image for use in an HTML
tag such as <img src= "icon.png"> ?

I typically put all my images in the img directory at the root of my web
host account. Now, in a production system this would simply translate to
http://www.mydomain.com/img/icon.png. But then on my development machine my
root directory is actually a virtual directory that is accessed as
http://localhost/mydomain/img/icon.png. That means that in production my
root is actually the domain root, while in the development system the root
is actually an application directory, a subdirectory of the IIS root.

In this case I am always stuck with the problem that I need to make the
control able to find its images easily (same goes for any stylesheet it may
need). Having to enter a root path in every instance of the control does not
sound very practical. Having to specify a web.config key for every instance
of the control also seems impractical, and hardcoding the key also sounds a
bit crappy.

I suppose there are much better ways to handle this so any input is
appreciated.

Regards,
Em.

 

[John Saunders]

This is something that has been nagging me over and over again and I think
there must be a better solution out there.

Some times (usually?) user controls and custom web controls need images
such
as icons and other decorations in the form of images. The problem is...
how
do you handle that in a way that everything is self-contained or at least
free form file system dependencies?

For example, the control needs a few icons and some background image for
part of the control. Is there a way to make it self-contained in the
Assembly? and if so, how can I extract/handle such image for use in an
HTML
tag such as <img src= "icon.png"> ?

You don't.

When the browser sees that <img> tag, it issues an HTTP request for
icon.png. The web server will either find that file and return it, or will
return an error. Having the file sitting around in your assembly just won't
do it, because the web server isn't going to go looking in your assembly.

Of course, the alternative would be to get the web browser to look in your
assembly.

You can do that by writing a custom HttpHandler and configuring the web site
to call it whenever there is a request for a particular resource. For
instance, you could put "icon.png" for a control called "MyControl" which
resides in a web application called "/app" in "/app/icon.png.MyControl". If
you configure the HttpHandler to process all requests for *.MyControl, then
it will be able to look in the assembly which MyControl is in for the
appropriate resources.

I typically put all my images in the img directory at the root of my web
host account. Now, in a production system this would simply translate to
http://www.mydomain.com/img/icon.png. But then on my development machine
my
root directory is actually a virtual directory that is accessed as
http://localhost/mydomain/img/icon.png. That means that in production my
root is actually the domain root, while in the development system the root
is actually an application directory, a subdirectory of the IIS root.

Try using "~/img/icon.png" in any server-side control. In particular:

<img runat="server" src="~/img/icon.png">

That will look in the appropriate place depending on where your application
is deployed.

John Saunders