Question

i’ve defined event type:

TMyEvent = procedure(object: TMyClass) of object;

and in the same unit i have also a class definition:

TMyClass = class(TObject)
    ...
  private
    FOnXXX: TMyEvent;
  protected
    ...
  public
    ...
    property OnXXX: TMyEvent read FOnXXX write FOnXXX;
  published
    { Published declarations }
  end;

If i try to compile i get ‘E2003 Undeclared identifier: ‘TMyEvent”.

In C++ i would use prototyping.
Is there a way to keep them in one unit together?

Sry, if it is a duplicate, but i really didn’t find any information about it.

Thanks in advance,
Peacelyk

Answer 1

You would forward declare the class before the event declaration:

TMyClass = class;
TMyEvent = procedure(object: TMyClass) of object;

Then you should include full declartion of TMyClass to resolve the unsatisfied forward declaration.