After extending a textbox with a NumberUpDownExtender, which comes with the AJAX Control Toolkit, I recieved the error “the number of fractional digits is out of range”. This happened when debugging my web application and using the extender. When using the web app in non-debug mode, nothing happened. This included the value change ‘not happening’.

Fortunately, this one was REALY easy, but it is not to be found on the web. That’s why I am posting this embarassing personal slip-up anyway. As it turned out, I switched the values in minimum and maximum. Make sure the Maximum property of the extender holds the highest value of the two and you should be good to go 😉

By the way, you would think something like this a) could be determined design- or compiletime, and b) could generate a better exception than ‘number of fractional digits out of range’.