Disable file associations depending on number of arguments

Archived from groups: microsoft.public.windowsnt.registry (More info?)

"Francisco del Valle" <f_delvalle@terra.es> wrote in
news:e6IwrpgAFHA.2156@TK2MSFTNGP10.phx.gbl:

> Hi.
>
> I've created a program similar to Unzip. It takes command line
> arguments like this:
>
> unzip file1
>
> I've added this Keys to Registry:
>
> HKEY_CLASSES_ROOT\MY_FILE_TYPE\Shell\MYZIP = "Unzip file"
> HKEY_CLASSES_ROOT\MY_FILE_TYPE\Shell\MYZIP\Command =
> "[PROGRAM_PATH]\MyUnZip.exe" %1
>
> My problem is: when I select more than one file to unzip, the program
> fails (windows open a program for each file). How can I disable this
> file associaton when the number of arguments is more than one?. I
> mean, I want that "Unzip file" only appear when I right click only one
> file.
>
>
> Sorry for my bad english.
>
> Thank you.
>
>
>

Windows does not create a command line that has more than one argument
when you do this. It creates a command line for each file that you have
selected. In your case, it will try to run one copy of your program for
each file you have selected.
Perhaps you can change your program so that it can run multiple instances
at the same time. For example, if you were using Winzip, it has an
option to "Reuse WinZip Windows" (which you can turn off) which causes it
to only run one instance at a time.