Newbie question about text boxes.

[ES5DWXL]

First, sorry if I posted at a wrong place or if this question is stupid question.

I am wanting to make a program what converts wavelengths to frequency and vice versa. However, there is a problem with a text box. Any value, even numeral value entered there is being treated like a text and therefore, if I want to do calculations, type mismatch error occurs. Is there any sorts of controls what allow inputting numbers?

Any help will be appreciated

[theo]

If I understand your question, you should probably learn the basics of Pascal first ;-)
http://www.delphibasics.co.uk/

You have to convert Strings to the type you wish to have like
StrToInt(..);
StrToIntDef(..);
StrToFloat(..);
....

You could also use TSpinEdit or TFloatSpinEdit, which only allow Integer or Single as input.

[ES5DWXL]

I must revise them then... I have done only command line programs before so I guess I need to take some extra classes