Basanagouda 0 Newbie Poster

I am able to Validate for 9.1 decimal Validation by regex expression "[0-9]\{0,9\}\.[0-9]?$" but If I call in KeyPress last character entered cannot be in textBoxVariable.text.
Qusetion : I want to do e.handle=true; for keypress , if textBoxVariable.text Value not satisfy regex condition.
Any solution?

Thanks in advance