Format exeption - why?

Hello,
:sign0013: i have a small problem, but can`t find the solution since hours.

I wrote a very small GPS-program and try to convert the speedoverground to Km/h.

this works fine:

textbox1.text = gps.speedoverground

this doesn`t:

textbox1.text = gps.speedoverground * 1.852


I recieve "format exeption". I tried several other ways, but always the same.

Thanks for answers.

This problem happens when there is no navigation data from the GPS.
In that case gps.SpeedOverGround returns "".
You can solve it with:
If gps.speedoverground = "" then textbox1.text = "0" else textbox1.text = gps.speedoverground * 1.852

Thank a lot, now I could go on very fast.

Btw, if there is a farmer speaking German here, please tell me. It would be nice to have someone who could test and understand my programs.

Im not a farmer But I speak german and have a GPS...