Question

type 
  TMyClass = class
  type
    PMyClass = ^TMyClass;
    TMyEvent = procedure(Sender: PmyClass) of object;
  public
    FTest: TMyEvent;
    procedure Test;
  end;

procedure TMyClass.Test;
begin
  FTest(@Self); //error!
end;

How do I do it?

Answer 1

What in the world are you trying to do? Of course you cannot call FTest since you haven’t assigned any TMyEvent to it yet! And are PMyClass and TMyEvent really supposed to be parts of TMyClass?

At least this works perfectly:

type
  PMyClass = ^TMyClass;
  TMyClass = class;

  TMyEvent = procedure(Sender: PMyClass) of object;

  TMyClass = class
  private
    FEvent: TMyEvent;
    FSomeValue: string;
  public
    property OnSomething: TMyEvent read FEvent write FEvent;
    property SomeValue: string read FSomeValue write FSomeValue;
    procedure Test;
  end;

  TSomeOtherClass = class
  public
    class procedure MyEvent(Sender: PMyClass);
  end;

...

procedure TForm6.FormCreate(Sender: TObject);
var
  o: TMyClass;
begin

  o := TMyClass.Create;
  o.SomeValue := 'This is a test.';
  o.OnSomething := TSomeOtherClass.MyEvent;

  o.Test;
end;

{ TMyClass }

procedure TMyClass.Test;
begin
  FEvent(@Self);
end;

{ TSomeOtherClass }

class procedure TSomeOtherClass.MyEvent(Sender: PMyClass);
begin
  ShowMessage(TMyClass(Sender^).SomeValue);
end;

Of course, you can also have the TMyEvent in the same object:

type
  TMyClass = class
  private type
    PMyClass = ^TMyClass;
    TMyEvent = procedure(Sender: PMyClass) of object;
  private
    FEvent: TMyEvent;
    FSomeValue: string;
  public
    procedure TheEventHandler(Sender: PMyClass);
    property OnSomething: TMyEvent read FEvent write FEvent;
    property SomeValue: string read FSomeValue write FSomeValue;
    procedure Test;
  end;

...

procedure TForm6.FormCreate(Sender: TObject);
var
  o: TMyClass;
begin

  o := TMyClass.Create;
  o.SomeValue := 'This is a test.';
  o.OnSomething := o.TheEventHandler;

  o.Test;
end;

{ TMyClass }

procedure TMyClass.Test;
begin
  FEvent(@Self);
end;

procedure TMyClass.TheEventHandler(Sender: PMyClass);
begin
  ShowMessage(TMyClass(Sender^).SomeValue);
end;