TStringList as field of object does not work

Question

uses Classes, SysUtils;

type
  TMyObject = class (TObject)
  private
    Fsl: TStringList;
  public
    constructor Create;
    destructor Destroy; override;
  end;

implementation

constructor TMyObject.Create;
begin
  Fsl := TStringList.Create;
end;

destructor TMyObject.Destroy;
begin
  FreeAndNil (Fsl);
  inherited;
end;

I get an access violation when the TStringList is created in the constructor.

This only happens if Fsl is declared as a field of TMyObject. If it is for example a global var, everything works as usual.

What am I doing wrong?

Answer 1

How do you create TMyObject?

It looks like the Access violation is because of the object self is not created.

So you should use:

myobject : TMyObject;
begin
  myobject := TMyObject.Create;

  // ...
end;

Answer 2

You have forgotten to call inherited in the constructor of your object (like you have called in destructor).

constructor TMyObject.Create;
begin
  inherited;
  Fsl := TStringList.Create;
end;

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Neftalí -Germán Estévez-