FormatException
value does not consist of an optional
sign followed by a sequence of digits
(0 through 9).
The exception that is thrown when the
format of an argument does not meet
the parameter specifications of the
invoked method.
You can use Int32.TryParse if you don't want to generate an exception like this.
Int32.TryParse: Converts the string representation of
a number to its 32-bit signed integer
equivalent. A return value indicates
whether the operation succeeded.
