Why from try catch, switch does not see the variable?

Question

C++ / C#

Why from try catch, switch does not see the variable?

Answer 1

Because curly braces in C# limit the scope of variables.
If you want the Number1 variable to be visible outside of the try block, you need to take it up a level.
Approximately like this:

double Number1 = 0;
try {
 // Тут пы инициализируем переменную
} catch {
  //Как-то обрабатываем возможную ошибку
}
// Тут мы можем использовать Number1

But since you are trying to handle an error when parsing numbers, then use the double.TryParse function instead of double.Parse - instead of throwing exceptions, it returns a flag whether the number was recognized successfully or not.