jvdblookupcomboedit.pas

East make Tray Icon in delphi

{-----------------------------------------------------------------------------
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: JvDBLookupEdit.PAS, released on 2003-09-18.
The Code was modified to: JvDBLookupComboEdit.PAS, released on 2003-10-20.

The Initial Developers of the Original Code are: Michael Habbe
Copyright (c) 2003 Michael Habbe
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:
=============

It must inherit from JvLookupEdit, because the new structure in JVCL3 produced
(in my environment) stack-overflow-errors, which "kicked" Delphi out of the
memory with only the message "Danger. Stack-Overflow. Save your work and restart
Delphi.". (The message is in German and i never saw it before!?)

I find out the problem in line 286 "or inherited ReadOnly;", when i uncommented
it, Delphi works, but i can modify the dataset, although i set ReadOnly to True.

As aforesaid, the component works in my Delphi with JVCL2, but as soon as i
inherit it with JVCL3 from JvDBLookupEdit, the specified errors occur.

Michael Habbe [2003-10-20]
-----------------------------------------------------------------------------}
// $Id: JvDBLookupComboEdit.pas,v 1.22 2005/02/18 14:17:23 ahuser Exp $

unit JvDBLookupComboEdit;

{$I jvcl.inc}

interface

uses
  {$IFDEF UNITVERSIONING}
  JclUnitVersioning,
  {$ENDIF UNITVERSIONING}
  Windows,
  {$IFDEF VCL}
  Messages,
  {$ENDIF VCL}
  Classes, Controls, Graphics, DB, DBCtrls,
  JvDBLookup;

type
  TJvDBLookupComboEdit = class(TJvDBLookupEdit)
  private
    FDataLink: TFieldDataLink;
    FCanvas: TControlCanvas;
    // FAlignment: TAlignment;
    FFocused: Boolean;
    FBeepOnError: Boolean;
    procedure ActiveChange(Sender: TObject);
    procedure DataChange(Sender: TObject);
    procedure EditingChange(Sender: TObject);
    function GetCanvas: TCanvas;
    function GetDataField: string;
    function GetDataSource: TDataSource;
    function GetField: TField;
    function GetTextMargins: TPoint;
    procedure ResetMaxLength;
    procedure SetDataField(const Value: string);
    procedure SetDataSource(Value: TDataSource);
    procedure SetFocused(Value: Boolean);
    procedure UpdateData(Sender: TObject);
    procedure WMPaint(var Msg: TWMPaint); message WM_PAINT;
    procedure CMGetDataLink(var Msg: TMessage); message CM_GETDATALINK;
  protected
    procedure WMCut(var Msg: TMessage); message WM_CUT;
    procedure WMPaste(var Msg: TMessage); message WM_PASTE;
    procedure WMUndo(var Msg: TMessage); message WM_UNDO;
    procedure DoEnter; override;
    procedure DoExit; override;

    function GetReadOnly: Boolean; override; // suppress the warning
    procedure SetReadOnly(Value: Boolean); override;
    procedure Change; override;
    function EditCanModify: Boolean; override;
    procedure KeyDown(var Key: Word; Shift: TShiftState); override;
    procedure KeyPress(var Key: Char); override;
    procedure Loaded; override;
    procedure Notification(AComponent: TComponent; Operation: TOperation); override;
    procedure Reset; override;
  public
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
    function ExecuteAction(Action: TBasicAction): Boolean; override;
    function UpdateAction(Action: TBasicAction): Boolean; override;
    // function UseRightToLeftAlignment: Boolean; override;
    property Field: TField read GetField;
    property Canvas: TCanvas read GetCanvas;
  published
    property Anchors;
    property AutoSelect;
    property AutoSize;
    property BeepOnError: Boolean read FBeepOnError write FBeepOnError default True;
    property BiDiMode;
    property BorderStyle;
    property CharCase;
    property Color;
    property Constraints;
    property DataField: string read GetDataField write SetDataField;
    property DataSource: TDataSource read GetDataSource write SetDataSource;
    property DragCursor;
    property DragKind;
    property DragMode;
    property Enabled;
    property Font;
    property ImeMode;
    property ImeName;
    property MaxLength;
    property ParentBiDiMode;
    property ParentColor;
    property ParentFont;
    property ParentShowHint;
    property PasswordChar;
    property PopupMenu;
    property ReadOnly: Boolean read GetReadOnly write SetReadOnly default False;
    property ShowHint;
    property TabOrder;
    property TabStop;
    property Visible;
    property OnChange;
    property OnClick;
    property OnContextPopup;
    property OnDblClick;
    property OnDragDrop;
    property OnDragOver;
    property OnEndDock;
    property OnEndDrag;
    property OnEnter;
    property OnExit;
    property OnKeyDown;
    property OnKeyPress;
    property OnKeyUp;
    property OnMouseDown;
    property OnMouseMove;
    property OnMouseUp;
    property OnStartDock;
    property OnStartDrag;
  end;

{$IFDEF UNITVERSIONING}
const
  UnitVersioning: TUnitVersionInfo = (
    RCSfile: '$RCSfile: JvDBLookupComboEdit.pas,v $';
    Revision: '$Revision: 1.22 $';
    Date: '$Date: 2005/02/18 14:17:23 $';
    LogPath: 'JVCL\run'
  );
{$ENDIF UNITVERSIONING}

implementation

uses
  SysUtils, Forms, StdCtrls,
  JvConsts;

constructor TJvDBLookupComboEdit.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  // inherited ReadOnly := True;
  ControlStyle := ControlStyle + [csReplicatable];
  FCanvas := TControlCanvas.Create;
  FCanvas.Control := Self;
  FDataLink := TFieldDataLink.Create;
  FDataLink.Control := Self;
  FDataLink.OnDataChange := DataChange;
  FDataLink.OnEditingChange := EditingChange;
  FDataLink.OnUpdateData := UpdateData;
  FDataLink.OnActiveChange := ActiveChange;
  FBeepOnError := True;
end;

destructor TJvDBLookupComboEdit.Destroy;
begin
  FDataLink.Free;
  FDataLink := nil;
  inherited Destroy;
  // (rom) destroy Canvas AFTER inherited Destroy
  FCanvas.Free;
end;

procedure TJvDBLookupComboEdit.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 TJvDBLookupComboEdit.Loaded;
begin
  inherited Loaded;
  ResetMaxLength;
  if csDesigning in ComponentState then
    DataChange(Self);
end;

procedure TJvDBLookupComboEdit.Notification(AComponent: TComponent;
  Operation: TOperation);
begin
  inherited Notification(AComponent, Operation);
  if (Operation = opRemove) and (FDataLink <> nil) and (AComponent = DataSource) then
    DataSource := nil;
end;

//function TJvDBLookupComboEdit.UseRightToLeftAlignment: Boolean;
//begin
//  Result := DBUseRightToLeftAlignment(Self, Field);
//end;

procedure TJvDBLookupComboEdit.KeyDown(var Key: Word; Shift: TShiftState);
begin
//  inherited KeyDown(Key, Shift);
//  if (Key = VK_DELETE) or ((Key = VK_INSERT) and (ssShift in Shift)) then
//    FDataLink.Edit;

  // new order, because result of inherited KeyDown(...) could be = 0
  // so, first set DataSet in Edit-Mode
  if Key in [VK_BACK, VK_DELETE, VK_UP, VK_DOWN, 32..255] then // taken from TDBComboBox.KeyDown(...)
    FDataLink.Edit;
  inherited KeyDown(Key, Shift);
end;

procedure TJvDBLookupComboEdit.KeyPress(var Key: Char);
begin
  inherited KeyPress(Key);
  if (Key in [#32..#255]) and (FDataLink.Field <> nil) and
    not FDataLink.Field.IsValidChar(Key) then
  begin
    if BeepOnError then
      SysUtils.Beep;
    Key := #0;
  end;
  case Key of
    CtrlH, CtrlV, CtrlX, #32..#255:
      FDataLink.Edit;
    Esc:
      begin
        FDataLink.Reset;
        SelectAll;
//        Key := #0;
      end;
  end;
end;

function TJvDBLookupComboEdit.EditCanModify: Boolean;
begin
  Result := FDataLink.Edit;
end;

procedure TJvDBLookupComboEdit.Reset;
begin
  FDataLink.Reset;
  SelectAll;
end;

procedure TJvDBLookupComboEdit.SetFocused(Value: Boolean);
begin
  if FFocused <> Value then
  begin
    FFocused := Value;
    // if (FAlignment <> taLeftJustify) and not IsMasked then Invalidate;
    FDataLink.Reset;
  end;
end;

procedure TJvDBLookupComboEdit.Change;
begin
  FDataLink.Modified;
  inherited Change;
end;

function TJvDBLookupComboEdit.GetDataSource: TDataSource;
begin
  Result := FDataLink.DataSource;
end;