la Procedure Notification

**saidus** · 30/08/2008, 13h56

Bonjour !!
J'ai un petit probleme
j'ai creer 2 classes, une qui descent de TPersistent(TOptionQuery) et l'autre de TMyQuery(TMyBaseQuery)
j'ai declarer une instance de la premiere dans la deuxieme

Code :

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 type 
    TOptionQuery = class(TPersistent)
     .....
    published 
     ..... 
       property CxEditor : TCxDBTextEditor read CxEditor write SetCxEditor ;
    end;
 
    TMyBaseQuery= class(TMyQuery)
    ....
    protected
       procedure Notification(AComponent: TComponent; Operation: TOperation); override;
    public
       constructor Create(AOwner: TComponent);override;
       Destructor Destroy; override;
       procedure Notification()
    published 
       property QOption: TOptionQuery read FQOption write FQOption;
    end;
// cxEditor est un control de type TDBEdit
........
 
procedure TMyBaseQuery.Notification(AComponent: TComponent; Operation: TOperation);
begin
  inherited Notification(AComponent,Operation);
    if (Operation=opRemove) and (AComponent=QOption.CxEditor) then
     QOption.CxEditor := nil;
end;

maintenant !! quand je pose le composant TmybaseQuery sur la forme et je relie sa properiete QOption.CxEditor a un composant de type TCxDBEditor (cxEdit1 )tout marche bien !!! mais le probleme survient lorsque je supprime ce dernier(cxEdit1),l'IDE delphi genere alors des messages d'erruer ...
et pourtant j'ai reecrit la procedure Notification .
que dois-je faire ...
merci pour votre aide

**neodelphi2007** · 30/08/2008, 23h36

Peut être faut il que tu supprime QOptions.Cxeditor avec FreeAndNil:

Code :

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procedure TMyBaseQuery.Notification(AComponent: TComponent; Operation: TOperation);
begin
  inherited Notification(AComponent,Operation);
    if (Operation=opRemove) and (AComponent=QOption.CxEditor) then
     FreeAndNil(QOption.CxEditor);
end;

**sjrd** · 31/08/2008, 00h02

Tu as oublié de demander au composant CxEditor de t'envoyer une notification

Pour cela, il faut appeler CxEditor.FreeNotification dans le SetCxEditor (et faire RemoveFreeNotification sur l'éventuelle ancienne valeur).
Tout est expliqué en détails là :
Sécuriser la destruction d'un composant référencé avec FreeNotification

**saidus** · 09/09/2008, 15h41

Bonjour Messieurs
Voici le Code que j'ai ecris et qui est toujours bogue ..
je ne sais pas ce qui m'echappe

Code :

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type
  TBSClientQuery = class ;
 
  TBSClientOption = class (TPersistent)
  private
    FClient : TBSClientQuery;
    FEditor: TcxDBTextEdit;
    FRequiredField_1: TStringField;
    FRequiredField_2: TStringField;
    FAskbeforeDelete: Boolean;
    FDeleteMsg: string;
    procedure SetEditor(const Value: TcxDBTextEdit);
    procedure SetRequiredField_1(const Value: TStringField);
    procedure SetRequiredField_2(const Value: TStringField);
    procedure CtrlDelete;
    procedure CtrlEditor;
    procedure CtrlEmptyField;
  protected
  public
    constructor Create(Client : TBSClientQuery);
    destructor Destroy ; override;
  published
    property RequiredField_1: TStringField read FRequiredField_1 write SetRequiredField_1;
    property RequiredField_2: TStringField read FRequiredField_2 write SetRequiredField_2;
    property Editor: TcxDBTextEdit read FEditor write SetEditor ;
    property DeleteMsg: string read FDeleteMsg write FDeleteMsg;
    property AskbeforeDelete: Boolean read FAskbeforeDelete write FAskbeforeDelete;
 
  end;
{ ==================================================================================== }
{  Exception Handler will intercept all exceptions in levels :                         }
{  ------------------------                                                            }
{   +   Before insert
    +   Before Post
    +   Before Edit
    +   Before Delete
    +   Before Cancel
    +   Before Refresh
}
  TBSClientQuery = class(TBSDataSet)
  private
    FAfterCancel: TDataSetNotifyEvent;
    FAfterDelete: TDataSetNotifyEvent;
    FAfterEdit: TDataSetNotifyEvent;
    FAfterInsert: TDataSetNotifyEvent;
    FAfterPost: TDataSetNotifyEvent;
    FBeforeCancel: TDataSetNotifyEvent;
    FBeforeDelete: TDataSetNotifyEvent;
    FBeforeEdit: TDataSetNotifyEvent;
    FBeforeInsert: TDataSetNotifyEvent;
    FBeforePost: TDataSetNotifyEvent;
    FClientOption: TBSClientOption;
    OldException : TExceptionEvent;
  protected
    procedure DoAfterCancel; override;
    procedure DoAfterDelete; override;
    procedure DoAfterEdit; override;
    procedure DoAfterInsert; override;
    procedure DoAfterPost; override;
    procedure DoBeforeCancel; override;
    procedure DoBeforeDelete; override;
    procedure DoBeforeEdit; override;
    procedure DoBeforeInsert; override;
    procedure DoBeforePost; override;
    procedure BSFireException(Sender:TObject;E:Exception);
    procedure BSInstallExecption;
    procedure BSUninstallException;
 
    procedure Notification(AComponent: TComponent; Operation: TOperation); override;
 
  public
    constructor Create(AOwner: TComponent); override;
    destructor  Destroy; override;
  published
    property BeforeInsert: TDataSetNotifyEvent read FBeforeInsert write FBeforeInsert;
    property AfterInsert: TDataSetNotifyEvent read FAfterInsert write FAfterInsert;
    property BeforeEdit: TDataSetNotifyEvent read FBeforeEdit write FBeforeEdit;
    property AfterEdit: TDataSetNotifyEvent read FAfterEdit write FAfterEdit;
    property BeforePost: TDataSetNotifyEvent read FBeforePost write FBeforePost;
    property AfterPost: TDataSetNotifyEvent read FAfterPost write FAfterPost;
    property BeforeCancel: TDataSetNotifyEvent read FBeforeCancel write FBeforeCancel;
    property AfterCancel: TDataSetNotifyEvent read FAfterCancel write FAfterCancel;
    property BeforeDelete: TDataSetNotifyEvent read FBeforeDelete write FBeforeDelete;
    property AfterDelete: TDataSetNotifyEvent read FAfterDelete write FAfterDelete;
 
    property ClientOption: TBSClientOption read FClientOption write FClientOption;
  end;
 
 
implementation
 
constructor TBSClientQuery.Create(AOwner: TComponent);
begin
  inherited;
  FClientOption := TBSClientOption.Create(Self);
end;
 
{ ------------------------------------------------------- }
{}
{ ------------------------------------------------------- }
destructor TBSClientQuery.Destroy;
begin
  FreeAndNil(FClientOption);
  inherited;
end;
 
{ ------------------------------------------------------- }
{}
{ ------------------------------------------------------- }
procedure TBSClientQuery.Notification(AComponent: TComponent;
  Operation: TOperation);
begin
  inherited Notification(AComponent,Operation);
  if (Operation = opRemove) and (AComponent=FClientOption.FEditor)          then
       FClientOption.FEditor          := nil;
  if (Operation = opRemove) and (AComponent=FClientOption.FRequiredField_1) then
       FClientOption.FRequiredField_1 := nil;
  if (Operation = opRemove) and (AComponent=FClientOption.FRequiredField_2) then
       FClientOption.FRequiredField_2 := nil;   
end;
 
.........
 
procedure TBSClientOption.SetEditor(const Value: TcxDBTextEdit);
begin
//  FEditor := Value;
//  CtrlEditor;
//{
//if FEditor<>nil then
//     FEditor.FreeNotification(FClient);
  if Assigned(FEditor) and (not (csDestroying in FEditor.ComponentState)) then
      FEditor.RemoveFreeNotification(FClient);
  FEditor := Value;
  if Assigned(FEditor) then
     FEditor.FreeNotification(FClient);
  CtrlEditor;
//     }
end;
 
{ ------------------------------------------------------- }
{}
{ -------------------------------------------------------} 
procedure TBSClientOption.SetRequiredField_1(const Value: TStringField);
begin
//  FRequiredField_1 := Value;
  if Assigned(FRequiredField_1) and (not (csDestroying in FRequiredField_1.ComponentState)) then
      FRequiredField_1.RemoveFreeNotification(FClient);
  FRequiredField_1 := Value;
  if Assigned(FRequiredField_1) then
     FRequiredField_1.FreeNotification(FClient);
end;
 
{ ------------------------------------------------------- }
{}
{ ------------------------------------------------------- }
procedure TBSClientOption.SetRequiredField_2(const Value: TStringField);
begin
//  FRequiredField_2 := Value;
  if Assigned(FRequiredField_2) and (not (csDestroying in FRequiredField_2.ComponentState)) then
      FRequiredField_2.RemoveFreeNotification(FClient);
  FRequiredField_2 := Value;
  if Assigned(FRequiredField_2) then
     FRequiredField_2.FreeNotification(FClient);
end;
 
 
constructor TBSClientOption.Create(Client: TBSClientQuery);
begin
  FClient := Client;
end;
 
destructor TBSClientOption.Destroy;
begin
  FClient := nil;
  inherited;
end;

merci pour votre aide !!

**sjrd** · 09/09/2008, 16h12

Euh non comme ça ça m'a l'air juste

Peux-tu nous dire si l'exécution passe bien par les méthodes concernées (les SetXXX et la procédure Notification). Il suffit de mettre un ShowMessage dans chacune.

**saidus** · 09/09/2008, 16h21

j'utilise l'utilitaire Eurekalog et j'ai le resultat suivant (voir le fichier text)
et quant je diagnostique l'erreur il me renvoie a la procedure de notification

**Aka Guymelef** · 09/09/2008, 16h26

Est-ce qu'il ne faudrait pas utiliser Self plutôt que FClient ? Parce que actuellement c'est FClient (le DataSet) qui reçoit les notifications alors que les affectations sont dans la propriété ClientOption qui appartient à FClient.

la Procedure Notification

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