Creating the Main Game Structure - Learning C# by Programming Games - page 334

catch (Exception e)
{
spriteBatch.DrawString(s + "is not a number", Vector2.Zero, Color.Red);
}
In the catch -part the exception is 'caught'. Behind the word catch , there is some
kind of parameter. Through this parameter it is possible to find out what exactly
went wrong. In the case of Parse , there are not a lot of options, but the parameter
has to be declared in any case, even if we do not use it.
In the body of the try -instruction, multiple instructions may be placed. But as
soon as an exception occurs, the execution is halted and the body of the catch is
executed. The remaining instructions after the try may therefore assume that there
was no exception if they are executed.
Watch out that the bodies of the try and the catch part need to be between braces,
even if there is only a single instruction in the body. This is a bit illogical, given that
the braces may be omitted in for example the if or while instructions.
The Exception type, of which we declared a variable after the catch , is a class with
all kinds of subclasses: FormatException , OverflowException , DivideByZeroException , and
so on. Each subclass differs in the kind of details that may be obtained from them
through accessing the properties. Instead of using these subclasses, you could sim-
ply use the Exception type between the parentheses after the catch keyword as we
did in the example code. However, this will catch an exception of any type, and you
will not know what kind of exception it is. Therefore, always catch exceptions by
using the subclasses, unless you have a good reason not to.
It is allowed to place multiple catch parts with one try -instruction. You can give
each of these catch parts a different exception type. When an exception occurs, the
first catch with a corresponding exception type is selected. For example:
try
{
n= int .Parse(s);
}
catch (FormatException e)
{
spriteBatch.DrawString(s + "is not a number", Vector2.Zero, Color.Red);
}
catch (OverflowException e)
{
spriteBatch.DrawString(s + "is too big", Vector2.Zero, Color.Red);
}
After the catch part, it is possible to place a finally part, which is executed no matter
whether an exception of a certain kind is caught or not. For example:
try
{
n= int .Parse(s);