🚀 go-pugleaf

Chris wrote:
> I have an app that registers itself with the shell allowing a user to right
> click a file and then select an option from the Windows pop-up menu.
> 
> All works fine until the user selects a lot of files, at which point this is
> the process the app follows:
> 
> 1 Windows starts a first instance of the app which receives the first file
> name as a command line arg.
> 2. Windows now starts a further instance of the app
> 3. This second instance uses a mutex to detect the first instance and if it
> finds one it sends a usermessage to the first instance and then closes.
> 4.  The first instance has a message loop that receives these usermessages
> and hence receives all further file names
> 
> All works fine but I want to present a message to the user asking whether
> they want to carry out an operation on all X files.  Clearly I cannot
> present this message until I know how many files there are.
> 

There are two ways to add a context menu handler to the Windows shell: 
The standard executable method and the COM shell extension -- 
IContextMenu -- method. The first way, which I assume you are using, is 
by far the easiest to implement, but it has limitations, and I think you 
may have reached them. I hate to suggest it, but because it allows for 
processing a list of files instead of passing them to your program one 
at a time, you may want to bite the bullet and look into writing a COM 
object.