Task filtering

[amorris]

I have written a program that allows users to dynamically add read and write tasks while the program runs. These task names are saved to a preferences file when you click 'apply' and then reloaded the next time the program runs. If a task is added for which hardware devices are not present, of course, the program throws an error. However, it also writes the troublesome task to my preferences file and will not allow me to apply new changes to correct that file programmatically. I have to manually open the file and change the text.

Is there a way to filter which I/O tasks are displayed to the user in an I/O control on the front panel? I would like some sort of "type matching" where I can check to see if the task has the right number of channels, data type, etc. that my program requires and not display the ones that don't. Alternately, any sort of type matching that would allow me to reject a user's selection that is invalid would be great.

Thanks!