TCollectionItem not initializing default property values

[djjd47130]

I've been fighting this crazy problem for hours and have gotten nowhere. I have this problem in two completely different projects using a TCollection. When a new collection item is added, I need to initialize the values of that item. However, they're not defaulting at all. I'm even setting them in two completely different places, in the item's constructor, and in the collection's add function - neither of them are working. I can set the values once the items are there, but I need to set default values. I've done collections in the past and never had this problem, I must be missing something here...

(Removed component and everything else from unit, there are a few references to this component so it won't compile)

unit JDGrids;

interface

uses
  Classes, Windows, SysUtils, Grids, StrUtils;

type
  TJDGridCol = class;
  TJDGridCols = class;  

  TJDGridCols = class(TCollection)
  private
    fOnEvent: TNotifyEvent;
  private
    fOwner: TComponent; 
    procedure DoEvent;
    property OnEvent: TNotifyEvent read fOnEvent write fOnEvent;
  protected
    function GetItem(Index: Integer): TJDGridCol;
    procedure SetItem(Index: Integer; Value: TJDGridCol);
    function GetOwner: TPersistent; override;
  public
    constructor Create(AOwner: TComponent); 
    destructor Destroy; override;
    function Add: TJDGridCol; 
    procedure Assign(Source: TPersistent); override;
    procedure Clear;
    procedure Delete(Index: Integer);
    property Items[Index: Integer]: TJDGridCol read GetItem write SetItem; default;
  end;

  TJDGridCol = class(TCollectionItem)
  private
    fOwner: TComponent;
    fWidth: Integer;
    fTitle: String;
    fCols: TJDGridCols;
    fOnEvent: TNotifyEvent;
    fVisible: Bool;
    procedure SetTitle(const Value: String);
    procedure SetWidth(const Value: Integer);
    procedure DoEvent;
    property OnEvent: TNotifyEvent read fOnEvent write fOnEvent;
    procedure SetVisible(const Value: Bool);
  protected
    function GetDisplayName: String; override;
  public
    constructor Create(AOwner: TJDGridCols);
    destructor Destroy; override;
  published
    property Title: String read fTitle write SetTitle;
    property Width: Integer read fWidth write SetWidth;
    property Visible: Bool read fVisible write SetVisible;
  end;

implementation

{ TJDGridCols }
      
constructor TJDGridCols.Create(AOwner: TComponent);
begin
  inherited Create(TJDGridCol);
  fOwner:= AOwner;
end;
       
destructor TJDGridCols.Destroy;
begin

  inherited Destroy;
end;

function TJDGridCols.Add: TJDGridCol;
begin
  Result:= TJDGridCol(inherited Add);
  Result.fCols:= Self; 
  Result.fTitle:= 'Column '+IntToStr(Result.ID);
  Result.fWidth:= 30;
  Result.fVisible:= True;
  DoEvent;
end;

procedure TJDGridCols.Assign(Source: TPersistent);
begin
  inherited Assign(Source);
  DoEvent;
end;

procedure TJDGridCols.Clear;
begin
  inherited Clear;
  DoEvent;
end;

procedure TJDGridCols.Delete(Index: Integer);
begin
  inherited Delete(Index);
  DoEvent;
end;

function TJDGridCols.GetItem(Index: Integer): TJDGridCol;
begin
  Result:= TJDGridCol(inherited Items[Index]);
end;

function TJDGridCols.GetOwner: TPersistent;
begin
  Result:= fOwner;
end;

procedure TJDGridCols.SetItem(Index: Integer; Value: TJDGridCol);
begin
  inherited Items[Index]:= Value;
  DoEvent;
end;

procedure TJDGridCols.DoEvent;
begin
  if assigned(fOnEvent) then fOnEvent(Self);
end;

{ TJDGridCol }

constructor TJDGridCol.Create(AOwner: TJDGridCols);
begin
  inherited Create(AOwner);
  fOwner:= AOwner.fOwner;
  fCols:= AOwner;
  fTitle:= 'Column '+IntToStr(ID);
  fWidth:= 30;
  fVisible:= True;
end;

destructor TJDGridCol.Destroy;
begin

  inherited Destroy;
end;

procedure TJDGridCol.DoEvent;
begin
  if assigned(fOnEvent) then fOnEvent(Self);
end;

function TJDGridCol.GetDisplayName: String;
begin
  Result:= fTitle;
end;

procedure TJDGridCol.SetTitle(const Value: String);
begin
  fTitle:= Value;
  DoEvent;
end;

procedure TJDGridCol.SetVisible(const Value: Bool);
begin
  fVisible := Value;  
  DoEvent;
end;

procedure TJDGridCol.SetWidth(const Value: Integer);
begin
  fWidth := Value; 
  DoEvent;
end;

end.

JD Solutions

 

[djjd47130]

Problem solved at StackOverflow:

http://stackoverflow.com/questions/...izing-default-property-values/8117647#8117647

JD Solutions