Какова роль оператора throw внутри блока catch в обработке исключений?

The throw operator inside a catch block is used to re-throw the current exception or throw a new one.

If you write just throw; without parameters, the exception is re-thrown with the original call stack preserved. This is useful when you want to handle the exception partially (for example, log it), and then pass it on.

If you write throw new Exception(...), a new exception is thrown, and the call stack will start from this point.

Example of re-throwing:

try
{
    // code
}
catch(Exception ex)
{
    Log(ex.Message);
    throw; // re-throw the same exception
}