Re: [DUG]: [Q] Component Property - Gives "Abstract Error"

[Nello Sestini]

I don't have the Dev Express components (AFAIK) so I can't duplicate exactly what you have.   But just for fun I tried the following:   type     TBaseDataLink = class(TPersistent);   TSimpleDataLink = class(TBaseDataLink);   TImage1 = class(TImage)   private       FDataLink : TSimpleDataLink;       FDonovan : boolean;       procedure SetDonovan(const Value : boolean);   protected     { Protected declarations }   public       constructor Create(AOwner : TComponent); override;       destructor Destroy; override;   published       property DataLink : TSimpleDataLink read FDataLink write FDataLink;       property Donovan : boolean read FDonovan write SetDonovan;   end;       none of my derived class functions "do" anything.   I can drop this thing onto a blank form with no errors.   I can also save and load the form - it saves like this:   object Form1: TForm1   Left = 629   Top = 112   Width = 1088   Height = 750   Caption = 'Form1'   Color = clBtnFace   Font.Charset = DEFAULT_CHARSET   Font.Color = clWindowText   Font.Height = -11   Font.Name = 'MS Sans Serif'   Font.Style = []   OldCreateOrder = False   PixelsPerInch = 96   TextHeight = 13   object Image11: TImage1     Left = 64     Top = 48     Width = 89     Height = 57     Donovan = False   end end     All this doesn't lead to much useful information.   Except it suggests that whatever is causing your "abstract error" and "reading Donovan" problems is something missing from my anaemic approximation.   Maybe something in TdxImageEdit (are there any members marked "abstract"?)  How about the TBaseDataLink class - is there more to it than appears here?   Maybe a bug in the way the DataLink property gets written to persistent store (like a missing or extra "<"?.     (Wild guesses).     weird stuff - wish i could be more helpful.   -ns                 ----- Original Message ----- From: Donovan J. Edye To: Multiple recipients of list delphi Sent: Thursday, August 23, 2001 6:56 AM Subject: [DUG]: [Q] Component Property - Gives "Abstract Error" G'Day All, I have the following component that is descended from a Dev Express TdxImageEdit control    TBaseDataLink = class(TPersistent)    TSimpleDataLink = class(TBaseDataLink) type    TADSSimpleEntity = class(TdxImageEdit)    private       FDataLink : TSimpleDataLink;       FDonovan : boolean;       procedure SetDonovan(const Value : boolean);    protected       { Protected declarations }    public       constructor Create(AOwner : TComponent); override;       destructor Destroy; override;    published       property DataLink : TSimpleDataLink read FDataLink write FDataLink;       property Donovan : boolean read FDonovan write SetDonovan;    end; Now the component compiles fine, but as soon as I drop it onto a form I get either: "Error reading ADSSimpleEntity1.Donovan: Abstract Error." or propery Donovan does not exist if I attempt to reference it in code. Has anyone got any ideas for me? The other DataLink property works without a problem. TIA -- Donovan ---------------------------------------------------------------------- Donovan J. Edye [www.edye.wattle.id.au] Namadgi Systems [www.namsys.com.au] Voice: +61 2 6285-3460 Fax: +61 2 6285-3459 TVisualBasic = Class(None); Heard just before the 'Big Bang': "...Uh Oh...." ---------------------------------------------------------------------- GXExplorer [http://www.gxexplorer.org] Freeware Windows Explorer replacement. Also includes freeware delphi windows explorer components. ----------------------------------------------------------------------