Componentes.Terceros.jvcl/official/3.36/run/JvDBCheckBox.pas

{-----------------------------------------------------------------------------
The contents of this file are subject to the Mozilla Public License
Version 1.1 (the "License"); you may not use this file except in compliance
with the License. You may obtain a copy of the License at
http://www.mozilla.org/MPL/MPL-1.1.html

Software distributed under the License is distributed on an "AS IS" basis,
WITHOUT WARRANTY OF ANY KIND, either expressed or implied. See the License for
the specific language governing rights and limitations under the License.

The Original Code is: JvDBCheckBox.pas, released on 2007-06-28.

The Initial Developer of the Original Code is Andreas Hausladen [andreas dott hausladen  att gmx dott de]
Portions created by Andreas Hausladen are Copyright (C) 2007 Andreas Hausladen.
All Rights Reserved.

Contributor(s): -

You may retrieve the latest version of this file at the Project JEDI's JVCL home page,
located at http://jvcl.sourceforge.net

Known Issues:
-----------------------------------------------------------------------------}
// $Id: JvDBCheckBox.pas 11641 2007-12-24 16:34:00Z outchy $

unit JvDBCheckBox;

{$I jvcl.inc}

interface

uses
  {$IFDEF UNITVERSIONING}
  JclUnitVersioning,
  {$ENDIF UNITVERSIONING}
  Windows, Messages, SysUtils, Classes, Contnrs, Controls, DB, DBCtrls;

type
  TJvDBCheckBoxChangingEvent = procedure(Sender: TObject; var Allow: Boolean) of object;

  TJvDBCheckBox = class(TDBCheckBox)
  private
    FDirectEdit: Boolean;
    FOnChange: TNotifyEvent;
    FOnChanging: TJvDBCheckBoxChangingEvent;
    FOrgDataChange: TNotifyEvent;
    FDataChanging: Integer;
    FToggling: Integer;
    FOldValue: Variant;

    procedure CMExit(var Message: TCMExit); message CM_EXIT;
    function GetDataLink: TFieldDataLink;
  protected
    procedure DataChange(Sender: TObject);

    procedure Toggle; override;
    function DoChanging: Boolean; virtual;
    procedure DoChange; virtual;
    procedure KeyPress(var Key: Char); override;
  public
    constructor Create(AOwner: TComponent); override;
  published
    property DirectEdit: Boolean read FDirectEdit write FDirectEdit default True;
    property OnChanging: TJvDBCheckBoxChangingEvent read FOnChanging write FOnChanging;
    property OnChange: TNotifyEvent read FOnChange write FOnChange;
  end;

{$IFDEF UNITVERSIONING}
const
  UnitVersioning: TUnitVersionInfo = (
    RCSfile: '$URL: https://jvcl.svn.sourceforge.net/svnroot/jvcl/branches/JVCL3_36_PREPARATION/run/JvDBCheckBox.pas $';
    Revision: '$Revision: 11641 $';
    Date: '$Date: 2007-12-24 17:34:00 +0100 (lun., 24 déc. 2007) $';
    LogPath: 'JVCL\run'
    );
{$ENDIF UNITVERSIONING}

implementation

{ TJvDBCheckBox }

constructor TJvDBCheckBox.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  FDirectEdit := True;
  FOrgDataChange := GetDataLink.OnDataChange;
  GetDataLink.OnDataChange := DataChange;
end;

procedure TJvDBCheckBox.CMExit(var Message: TCMExit);
begin
  if DirectEdit then
  begin
    if GetDataLink.Active and (Field <> nil) then
      FOldValue := Field.Value;
    DoExit // TWinControl behaviour
  end
  else
    inherited;
end;

procedure TJvDBCheckBox.DoChange;
begin
  if Assigned(FOnChange) then
    FOnChange(Self);
end;

procedure TJvDBCheckBox.Toggle;
begin
  if FDataChanging = 0 then
  begin
    if not DoChanging then
      Exit;
  end;

  Inc(FToggling);
  try
    inherited Toggle;
    if DirectEdit and (FDataChanging = 0) and GetDataLink.Active and GetDataLink.Editing then
      GetDataLink.UpdateRecord;
  finally
    Dec(FToggling);
  end;

  if FDataChanging = 0 then
    DoChange;
end;

function TJvDBCheckBox.DoChanging: Boolean;
begin
  Result := True;
  if Assigned(FOnChanging) then
    FOnChanging(Self, Result);
end;

function TJvDBCheckBox.GetDataLink: TFieldDataLink;
begin
  Result := TFieldDataLink(Perform(CM_GETDATALINK, 0, 0));
end;

procedure TJvDBCheckBox.KeyPress(var Key: Char);
begin
  case Key of
    #27:
      if (Field <> nil) and (DataSource <> nil) and (DataSource.State in [dsEdit, dsInsert]) then
        Field.Value := FOldValue;
  end;
  inherited KeyPress(Key);
end;

procedure TJvDBCheckBox.DataChange(Sender: TObject);
begin
  if (FToggling = 0) and DirectEdit and (Field <> nil) then
    FOldValue := Field.Value;

  Inc(FDataChanging);
  try
    FOrgDataChange(Sender);
  finally
    Dec(FDataChanging);
  end;
end;

initialization
  {$IFDEF UNITVERSIONING}
  RegisterUnitVersion(HInstance, UnitVersioning);
  {$ENDIF UNITVERSIONING}

finalization
  {$IFDEF UNITVERSIONING}
  UnregisterUnitVersion(HInstance);
  {$ENDIF UNITVERSIONING}

end.