Meu componente está com access violation (código no post)

unit DBEditRequerido;

interface

uses
  SysUtils, Classes, Controls, StdCtrls, Mask, DBCtrls, Graphics, Messages, DB;

type
  TDBEditRequerido = class(TDBEdit)
  private
    { Private declarations }
     FCorFundo : TColor;
     FCorFonte : TColor;
     FLigado: Boolean;
     FDataLink: TFieldDataLink;
     procedure AjustaCorFundo(Value: TColor);
     procedure AjustaCorFonte(Value: TColor);
     procedure AjustaLigado(Value: Boolean);
     procedure SetDataField(const Value: WideString);
     function GetDataField: WideString;
     procedure ResetMaxLength;
     procedure PerdeFoco(var Message: TCMExit); message CM_EXIT;
  protected
    { Protected declarations }
  public
    { Public declarations }
    constructor Create(AOwner: TComponent); override;
  published
    { Published declarations }
    property CorFundo : TColor  read FCorFundo  write AjustaCorFundo;
    property CorFonte : TColor  read FCorFonte  write AjustaCorFonte;
    property Ligado   : Boolean read FLigado write AjustaLigado;
    property DataField: WideString read GetDataField write SetDataField;
  end;

procedure Register;

implementation

procedure Register;
begin
   RegisterComponents(´Meus Componentes´, [TDBEditRequerido]);
end;

{ TDBEditRequerido }

procedure TDBEditRequerido.AjustaCorFundo(Value: TColor);
begin
   if (Value <> FCorFundo) then
   begin
      FCorFundo := Value;
      Self.Color := Value;
   end;
end;

function TDBEditRequerido.GetDataField: WideString;
begin
  Result := FDataLink.FieldName;
end;

procedure TDBEditRequerido.SetDataField(const Value: WideString);
begin
  if not (csDesigning in ComponentState) then
     ResetMaxLength;
  FDataLink.FieldName := Value;

  if Self.Field.Required Then
   begin
      FCorFundo := $00CACAFF;
      FCorFonte := clBlack;

      Self.Color := $00CACAFF;
      Self.Font.Color := clBlack;
   end;
end;

procedure TDBEditRequerido.ResetMaxLength;
var
  F: TField;
begin
  if (MaxLength > 0) and Assigned(DataSource) and Assigned(DataSource.DataSet) then
  begin
    F := DataSource.DataSet.FindField(DataField);
    if Assigned(F) and (F.DataType in [ftString, ftWideString]) and (F.Size = MaxLength) then
      MaxLength := 0;
  end;
end;

procedure TDBEditRequerido.AjustaLigado(Value: Boolean);
begin
   if (Value <> FLigado) then
   begin
      FLigado := Value;

      if Not FLigado then
      begin
         AjustaCorFundo(clWhite);
         AjustaCorFonte(clBlack);
      end else
      begin
         AjustaCorFundo(FCorFundo);
         AjustaCorFonte(FCorFonte);
      end;
   end;
end;

procedure TDBEditRequerido.AjustaCorFonte(Value: TColor);
begin
   if (Value <> FCorFonte) then
   begin
      FCorFonte := Value;
      Self.Font.Color := Value;
   end;
end;

procedure TDBEditRequerido.PerdeFoco(var Message: TCMExit);
begin

   If FLigado And Self.Field.Required Then
   begin
      if Trim(Self.Text) <> ´´ then
      begin
         FCorFundo := clWhite;
         FCorFonte := clBlack;

         Self.Color := clWhite;
         Self.Font.Color := clBlack;
      end else
      begin
         FCorFundo := $00CACAFF;
         FCorFonte := clBlack;

         Self.Color := $00CACAFF;
         Self.Font.Color := clBlack;
      end;
   end;
end;

constructor TDBEditRequerido.Create(AOwner: TComponent);
begin
   inherited Create(AOwner);

   FLigado := True;
   FCorFundo := $00CACAFF;
   FCorFonte := clBlack;
end;

end.