Allow only positive number with text input mask

I true to set a text input 开发者_如何学Pythonmask which only allow numbers from 0-999, or even better 1-999.

So I tried the mask "##0", but unfortunately this also allows negative numbers. Is there a way to allow only positive numbers?

Best regards, Enyra

990 should work just fine as far as I understand your question. This will make space an allowed character for the two first digits, and the last one is always required to be a number.