{*******************************************************}
{                                                       }
{         Delphi VCL Extensions (RX)                    }
{                                                       }
{         Copyright (c) 1997 Master-Bank                }
{                                                       }
{*******************************************************}

unit rxdbcomb;

{$I rx.inc}

interface

uses LCLType, LCLProc, LCLIntf, LMessages, Menus, Graphics, Classes, Controls,
  DB, StdCtrls, DbCtrls;

type

{ TCustomDBComboBox }

  TCustomDBComboBox = class(TCustomComboBox)
  private
    FDataLink: TFieldDataLink;
    procedure DataChange(Sender: TObject);
    procedure EditingChange(Sender: TObject);
    function GetDataField: string;
    function GetDataSource: TDataSource;
    function GetField: TField;
    function GetReadOnly: Boolean;
    procedure SetDataField(const Value: string);
    procedure SetDataSource(Value: TDataSource);
    procedure SetEditReadOnly;
    procedure SetItems(const Value: TStrings);
    procedure SetReadOnly(Value: Boolean);
    procedure UpdateData(Sender: TObject);
    function GetComboText: string; virtual;
    procedure SetComboText(const Value: string); virtual;
  protected
    procedure EditingDone; override;
    procedure Change; override;
    procedure Click; override;
    procedure CreateWnd; override;
    procedure DropDown; override;
    function GetPaintText: string; virtual;
    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 SetStyle(Value: TComboBoxStyle); override;
    procedure WndProc(var Message: TLMessage); override;
    property ComboText: string read GetComboText write SetComboText;
    property DataField: string read GetDataField write SetDataField;
    property DataSource: TDataSource read GetDataSource write SetDataSource;
    property ReadOnly: Boolean read GetReadOnly write SetReadOnly default False;
  public
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
    function ExecuteAction(AAction: TBasicAction): Boolean; override;
    function UpdateAction(AAction: TBasicAction): Boolean; override;
    function UseRightToLeftAlignment: Boolean;
    property Field: TField read GetField;
    property Items write SetItems;
    property Text;
  end;

{ TRxDBComboBox }

  TRxDBComboBox = class(TCustomDBComboBox)
  private
    FValues: TStrings;
    FEnableValues: Boolean;
    procedure SetEnableValues(Value: Boolean);
    procedure SetValues(Value: TStrings);
    procedure ValuesChanged(Sender: TObject);
  protected
    procedure SetStyle(Value: TComboBoxStyle); override;
    function GetComboText: string; override;
    function GetPaintText: string; override;
    procedure SetComboText(const Value: string); override;
  public
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
  published
    property Anchors;
    property ArrowKeysTraverseList;
    property AutoDropDown;
    property AutoSize;
    property BorderSpacing;
    property Style; { must be published before Items }
    property Color;
    property DataField;
    property DataSource;
    property DragMode;
    property DragCursor;
    property DropDownCount;
    property Enabled;
    property EnableValues: Boolean read FEnableValues write SetEnableValues;
    property Font;
    property Constraints;
    property DragKind;
    property ItemHeight;
    property Items;
    property ItemWidth;
    property MaxLength default -1;
    property ParentColor;
    property ParentFont;
    property ParentShowHint;
    property PopupMenu;
    property ReadOnly;
    property ShowHint;
    property Sorted;
    property TabOrder;
    property TabStop;
    property Values: TStrings read FValues write SetValues;
    property Visible;
    property OnChange;
    property OnChangeBounds;
    property OnClick;
    property OnCloseUp;
    property OnDblClick;
    property OnDragDrop;
    property OnDragOver;
    property OnDrawItem;
    property OnDropDown;
    property OnEndDrag;
    property OnEnter;
    property OnExit;
    property OnKeyDown;
    property OnKeyPress;
    property OnKeyUp;
    property OnMeasureItem;
    property OnMouseDown;
    property OnMouseMove;
    property OnMouseUp;
    property OnSelect;
    property OnStartDrag;
    property OnUTF8KeyPress;
    property OnContextPopup;
    property OnEndDock;
    property OnStartDock;
  end;

implementation

uses DBUtils;

{ TCustomDBComboBox }

constructor TCustomDBComboBox.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  ControlStyle := ControlStyle + [csReplicatable];
  FDataLink := TFieldDataLink.Create;
  FDataLink.Control := Self;
  FDataLink.OnDataChange := @DataChange;
  FDataLink.OnUpdateData := @UpdateData;
  FDataLink.OnEditingChange := @EditingChange;
end;

destructor TCustomDBComboBox.Destroy;
begin
  FDataLink.OnDataChange := nil;
  FDataLink.OnUpdateData := nil;
  FDataLink.Free;
  FDataLink := nil;
  inherited Destroy;
end;

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

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

procedure TCustomDBComboBox.CreateWnd;
begin
  inherited CreateWnd;
  SetEditReadOnly;
end;

procedure TCustomDBComboBox.DataChange(Sender: TObject);
begin
  if DroppedDown then Exit;
  if FDataLink.Field <> nil then ComboText := FDataLink.Field.AsString
  else if csDesigning in ComponentState then ComboText := Name
  else ComboText := '';
end;

procedure TCustomDBComboBox.UpdateData(Sender: TObject);
begin
  FDataLink.Field.AsString := ComboText;
end;

procedure TCustomDBComboBox.SetComboText(const Value: string);
var
  I: Integer;
  Redraw: Boolean;
begin
  if Value <> ComboText then
  begin
    if Style <> csDropDown then
    begin
      Redraw := (Style <> csSimple) and HandleAllocated;
//      if Redraw then SendMessage(Handle, LM_SETREDRAW, 0, 0);
      try
        if Value = '' then I := -1 else I := Items.IndexOf(Value);
        ItemIndex := I;
      finally
        if Redraw then
        begin
//          SendMessage(Handle, WM_SETREDRAW, 1, 0);
          Invalidate;
        end;
      end;
      if I >= 0 then Exit;
    end;
    if Style in [csDropDown, csSimple] then Text := Value;
  end;
end;

function TCustomDBComboBox.GetComboText: string;
var
  I: Integer;
begin
  if Style in [csDropDown, csSimple] then Result := Text
  else
  begin
    I := ItemIndex;
    if I < 0 then Result := '' else Result := Items[I];
  end;
end;

procedure TCustomDBComboBox.Change;
begin
  FDataLink.Edit;
  FDataLink.Modified;
  FDataLink.UpdateRecord;
  inherited Change;
end;

procedure TCustomDBComboBox.Click;
begin
  FDataLink.Edit;
  inherited Click;
  FDataLink.Modified;
end;

procedure TCustomDBComboBox.DropDown;
begin
  FDataLink.Edit;
  inherited DropDown;
end;

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

procedure TCustomDBComboBox.SetDataSource(Value: TDataSource);
begin
  if not (FDataLink.DataSourceFixed and (csLoading in ComponentState)) then
    FDataLink.DataSource := Value;
  if Value <> nil then Value.FreeNotification(Self);
end;

function TCustomDBComboBox.GetDataField: string;
begin
  Result := FDataLink.FieldName;
end;

procedure TCustomDBComboBox.SetDataField(const Value: string);
begin
  FDataLink.FieldName := Value;
end;

function TCustomDBComboBox.GetReadOnly: Boolean;
begin
  Result := FDataLink.ReadOnly;
end;

procedure TCustomDBComboBox.SetReadOnly(Value: Boolean);
begin
  FDataLink.ReadOnly := Value;
end;

function TCustomDBComboBox.GetField: TField;
begin
  Result := FDataLink.Field;
end;

procedure TCustomDBComboBox.KeyDown(var Key: Word; Shift: TShiftState);
begin
  inherited KeyDown(Key, Shift);
  if (Key = VK_BACK) or (Key = VK_DELETE) or (Key = VK_UP) or
     (Key = VK_DOWN) or (Key in [32..255]) then
  begin
    if not FDataLink.Edit and (Key in [VK_UP, VK_DOWN]) then
      Key := 0;
  end;
end;

procedure TCustomDBComboBox.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
//    MessageBeep(0);
    Key := #0;
  end;
  case Key of
    ^H, ^V, ^X, #32..#255:
      FDataLink.Edit;
    #27:
      begin
        FDataLink.Reset;
        SelectAll;
      end;
  end;
end;

procedure TCustomDBComboBox.EditingChange(Sender: TObject);
begin
  SetEditReadOnly;
end;

procedure TCustomDBComboBox.SetEditReadOnly;
begin
(*  if (Style in [csDropDown, csSimple]) and HandleAllocated then
    SendMessage({$IFDEF WIN32} EditHandle {$ELSE} FEditHandle {$ENDIF},
      EM_SETREADONLY, Ord(not FDataLink.Editing), 0); *)
end;


procedure TCustomDBComboBox.WndProc(var Message: TLMessage);
begin
  if not (csDesigning in ComponentState) then
    case Message.Msg of
      LM_COMMAND:
        if TLMCommand(Message).NotifyCode = CBN_SELCHANGE then
          if not FDataLink.Edit then begin
{            if Style <> csSimple then
              PostMessage(Handle, LB_SHOWDROPDOWN, 0, 0);}
            Exit;
          end;
{      CB_SHOWDROPDOWN:
        if Message.WParam <> 0 then FDataLink.Edit
        else if not FDataLink.Editing then DataChange(Self); }{Restore text}
{$IFDEF WIN32}
{      LM_CREATE,
      WM_WINDOWPOSCHANGED,
      CM_FONTCHANGED:
        FPaintControl.DestroyHandle;}
{$ENDIF}
    end;
  inherited WndProc(Message);
end;

procedure TCustomDBComboBox.EditingDone;
begin
  if Assigned(FDataLink.DataSet) and (FDataLink.DataSet.State in [dsinsert,dsedit]) then
  begin
    try
      FDataLink.UpdateRecord;
    except
      SelectAll;
      if CanFocus then SetFocus;
      raise;
    end;
    inherited EditingDone;
  end;
end;


function TCustomDBComboBox.GetPaintText: string;
begin
  if FDataLink.Field <> nil then Result := FDataLink.Field.Text
  else Result := '';
end;

procedure TCustomDBComboBox.SetItems(const Value: TStrings);
begin
  Items.Assign(Value);
  DataChange(Self);
end;

procedure TCustomDBComboBox.SetStyle(Value: TComboBoxStyle);
begin
  if (Value = csSimple) and Assigned(FDatalink) and FDatalink.DatasourceFixed then
    _DBError('SNotReplicatable');
  inherited SetStyle(Value);
end;

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

function TCustomDBComboBox.ExecuteAction(AAction: TBasicAction): Boolean;
begin
{  Result := inherited ExecuteAction(AAction) or (FDataLink <> nil) and
    FDataLink.ExecuteAction(AAction);}
end;

function TCustomDBComboBox.UpdateAction(AAction: TBasicAction): Boolean;
begin
{  Result := inherited UpdateAction(AAction) or (FDataLink <> nil) and
    FDataLink.UpdateAction(AAction);}
end;

{ TRxDBComboBox }

constructor TRxDBComboBox.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  FValues := TStringList.Create;
  TStringList(FValues).OnChange := @ValuesChanged;
  EnableValues := False;
end;

destructor TRxDBComboBox.Destroy;
begin
  TStringList(FValues).OnChange := nil;
  FValues.Free;
  inherited Destroy;
end;

procedure TRxDBComboBox.ValuesChanged(Sender: TObject);
begin
  if FEnableValues then DataChange(Self);
end;

function TRxDBComboBox.GetPaintText: string;
var
  I: Integer;
begin
  Result := '';
  if FDataLink.Field <> nil then begin
    if FEnableValues then begin
      I := Values.IndexOf(FDataLink.Field.Text);
      if I >= 0 then Result := Items.Strings[I]
    end
    else Result := FDataLink.Field.Text;
  end;
end;

function TRxDBComboBox.GetComboText: string;
var
  I: Integer;
begin
  if (Style in [csDropDown, csSimple]) and (not FEnableValues) then
    Result := Text
  else begin
    I := ItemIndex;
    if (I < 0) or (FEnableValues and (FValues.Count < I + 1)) then
      Result := ''
    else
      if FEnableValues then Result := FValues[I]
      else Result := Items[I];
  end;
end;

procedure TRxDBComboBox.SetComboText(const Value: string);
var
  I: Integer;
  Redraw: Boolean;
begin
  if Value <> ComboText then
  begin
    if Style <> csDropDown then
    begin
      Redraw := (Style <> csSimple) and HandleAllocated;
//      if Redraw then SendMessage(Handle, WM_SETREDRAW, 0, 0);
      try
        if Value = '' then I := -1
        else
          if FEnableValues then I := Values.IndexOf(Value)
          else I := Items.IndexOf(Value);
        if I >= Items.Count then I := -1;
        ItemIndex := I;
      finally
        if Redraw then
        begin
//          SendMessage(Handle, WM_SETREDRAW, 1, 0);
//          Invalidate;
        end;
      end;
      if I >= 0 then Exit;
    end;
    if Style in [csDropDown, csSimple] then Text := Value;
    Invalidate;
  end;
end;

procedure TRxDBComboBox.SetEnableValues(Value: Boolean);
begin
  if FEnableValues <> Value then
  begin
    if Value and (Style in [csDropDown, csSimple]) then
      Style := csDropDownList;
    FEnableValues := Value;
    DataChange(Self);
  end;
end;

procedure TRxDBComboBox.SetValues(Value: TStrings);
begin
  FValues.Assign(Value);
end;

procedure TRxDBComboBox.SetStyle(Value: TComboboxStyle);
begin
  if (Value in [csSimple, csDropDown]) and FEnableValues then
    Value := csDropDownList;
  inherited SetStyle(Value);
end;

end.