I don't like visual development tools that are supposed to write a program for me. Even if it is Xcode and I can use Interface Builder. Yes, it is a perfect tool and has helped me a lot, mainly, in the beginning, when my programs were small…
This Article will show you how to validate number with TEdit control,
What's the TEdit control?
TEdit is a standard Windows edit control on a form, it allows to user to write, read and copy/paste single line of text.