Good day! Please tell me what is the meaning of the design On E: Exception Do? What is E? Do I understand correctly that this construct responds to any exception?

    2 answers 2

    E is an object of class Exception. Yes, this construction really reacts to any exception, further processing boils down to determining the type (for example,

    E.ClassName

    ) and the output of the message (for example,

     E.Message

    ), or other action.

    All exceptions:

     except On E : Exception do ShowMessage('Error: '+E.Message); end;

    Optional:

     except // Ошибка ввода-вывода On E : EInOutError do ShowMessage('IO error : '+E.Message); // Деление на ноль On E : EDivByZero do ShowMessage('Div by zero error : '+E.Message); // Все остальное: else ShowMessage('Unknown error'); end;

    Something like Switch / case + default

      I will add

      if you need an exception of the EOutOfMemory type, then

       on E: Exception do // или on E: EOutOfMemory do if E is EOutOfMemory then

      and if you need a whole of all derivatives (eg EMyMemoryError = class (EOutOfMemory)), then so:

       on E: EOutOfMemory do
      • not at all =) - ADR