unit jvclEDBGRID;


interface

uses
	jvDBGrid,
  SysUtils, Classes, Grids, Controls, DB, DBGrids, Graphics, Forms, WinTypes, Messages;

type
  TjvclEDBGrid = class(TJvDBGrid)
  private
    iCurrentObj: integer;
    ColumnHasObj: boolean;
    ShowObject: boolean;
    fResizeObjects : Boolean;
    GridObjs: TList;
    FOnMouseDown: TMouseEvent;
    function GetObjIndex (const GridIndex: integer): integer;
    procedure WMSetFocus(var Msg: TWMSetFocus); message WM_SETFOCUS;
    procedure WMGetDlgCode(var Msg: TWMGetDlgCode); message WM_GETDLGCODE;
  protected
    procedure Loaded; override;
    procedure SetColumnAttributes; override;
    procedure MouseDown(Button: TMouseButton; Shift: TShiftState; X,Y: Integer); override;
    procedure KeyPress(var Key: Char); override;
    {$ifdef WIN32}
    procedure DrawColumnCell(const Rect: TRect; DataCol: Integer;
      Column: TColumn; State: TGridDrawState); override;
    {$else}
    procedure DrawDataCell(const Rect: TRect; Field: TField; State: TGridDrawState); override;
    {$endif}
  public
    ObjEnabled: boolean;
    Property Row;
    Property Col;
    constructor Create(AOwner:TComponent); override;
    destructor Destroy; override;
  published
  	property ResizeChildObjects : Boolean read fResizeObjects Write fResizeObjects;
  	property EnableChildObjects : Boolean read ObjEnabled Write objEnabled;
    property OnMouseDown read FOnMouseDown write FOnMouseDown;
    Property OnMouseMove;
    Property OnMouseUp;
  end;

procedure Register;

implementation

{______________________________________________________________________________}
procedure Register;
begin
  RegisterComponents('VNM', [TjvclEDBGrid]);
end;

{______________________________________________________________________________}
constructor TjvclEDBGrid.Create (AOwner:TComponent);
begin
  inherited Create(AOwner);
  ControlStyle := ControlStyle + [csAcceptsControls];
  ObjEnabled := true;
  iCurrentObj := -1;                           {current visible embedded object}
  ShowObject := false;                    {show only when KeyPress or MouseDown}
  ColumnHasObj := false;
  GridObjs := TList.Create;
  {My Defaults (you may change or delete this to suit your needs)}
  Options := Options - [dgConfirmDelete,dgColumnResize];
  TitleFont.Style := [];
  Height := 142;
end;

{______________________________________________________________________________}
destructor TjvclEDBGrid.Destroy;
begin
  inherited Destroy;
  GridObjs.Free;
  GridObjs := nil;
  {$IFNDEF WIN32}
  try
    TitleFont.Free;                                   {fix Delphi 1 memory leak}
    TitleFont:=Nil;
  except
  end;
  {$ENDIF}
end;

{______________________________________________________________________________}
procedure TjvclEDBGrid.Loaded;
begin
  Inherited Loaded;
  if csDesigning in ComponentState then Exit;
  {move all objects from Controls property to GridObjs}
  {Notice: this is necessary because some controls (TComboBox, for example)
   don't "behave" themselves when having the grid as parent (Who knows why?)}
  while ControlCount > 0 do begin
    {hide all embedded objects}
    Controls[ControlCount-1].Visible := false;
    {move objects to GridObjs}
    GridObjs.Add(Controls[ControlCount-1]);
    TControl(GridObjs[GridObjs.Count-1]).Parent := Parent;
  end;
end;

{______________________________________________________________________________}
procedure TjvclEDBGrid.SetColumnAttributes;
var
  i: Integer;
begin
  inherited SetColumnAttributes;
  {tell the grid to stop at each embedded object}
  for i := 1 to FieldCount do
    if not TabStops[i] then
      TabStops[i] := (GetObjIndex(i-1) <> -1);
end;

{______________________________________________________________________________}
function TjvclEDBGrid.GetObjIndex (const GridIndex: integer): integer;
var
  i: integer;
begin
  result := -1;
  for i := 0 to GridObjs.Count-1 do
    {each embedded object must have a corresponding Calculated Field}
    if CompareText(TControl(GridObjs[i]).Name, Fields[GridIndex].FieldName) = 0 then begin
      result := i;
      break
    end;
end;

{______________________________________________________________________________}
procedure TjvclEDBGrid.MouseDown(Button: TMouseButton; Shift: TShiftState; X,Y: Integer);
begin
  if Assigned(FOnMouseDown) then
     FOnMouseDown(Self,Button,Shift,X,Y);
  inherited MouseDown(Button, Shift, X, Y);
  {show current embedded object}
  ShowObject := true;
  DrawCell(Col,Row,CellRect(Col,Row),[gdFocused,gdSelected]);
end;

{______________________________________________________________________________}
procedure TjvclEDBGrid.KeyPress(var Key: Char);
begin
  inherited KeyPress(Key);
  {show current embedded object, if need be}
  if ColumnHasObj and (Key <> #9) then begin
    ShowObject := true;
    DrawCell(Col,Row,CellRect(Col,Row),[gdFocused]);
  end;
end;

{ Mod so that a control which is not resized to fit the column, appears right aligned to the column
 if it is near the right side of the grid control}
{______________________________________________________________________________}
{$ifdef WIN32}
procedure TjvclEDBGrid.DrawColumnCell(const Rect: TRect; DataCol: Integer;
                                  Column: TColumn; State: TGridDrawState);
{$else}
procedure TjvclEDBGrid.DrawDataCell(const Rect: TRect; Field: TField;
                                State: TGridDrawState);
{$endif}
begin
	{$ifdef WIN32}
		inherited DrawColumnCell(Rect,DataCol,Column,State);
	{$else}
		inherited DrawDataCell(Rect,Field,State);
	{$endif}

	if (gdFocused in State) and ObjEnabled then begin
		{check if there's a visible object then hide it}
		if iCurrentObj <> -1 then begin
			TControl(GridObjs[iCurrentObj]).Visible := false;
            iCurrentObj := -1;
        end;
        {check if the current column has an enbedded object then show it}
        if ShowObject then begin
        	iCurrentObj := GetObjIndex(SelectedIndex);
            if iCurrentObj <> -1 then
            	with TControl(GridObjs[iCurrentObj]) do
                begin
            		if fResizeObjects = true then
                    	{ Resize control to fit cell }
                		Setbounds(Rect.Left + Self.Left, Rect.Top + Self.Top,
                        	Rect.Right - Rect.Left,Height)
                	else
                    begin
                    	{ handle right align if required }
                        if (Rect.Left + self.Left + width) > (self.Left + self.Width) then
							Setbounds(Rect.Right + Self.Left - width ,
                            	Rect.Top + Self.Top, Width, Height)
                        else
                        	{ Normal left align }
							Setbounds(Rect.Left + Self.Left,
                            	Rect.Top + Self.Top, Width, Height);
                    end;
                	{make it visible and give it focus}
                	Visible := true;
                	TWinControl(GridObjs[iCurrentObj]).SetFocus;
      			end;
      		ShowObject := false;
    	end;
	end;
end;

{______________________________________________________________________________}
procedure TjvclEDBGrid.WMSetFocus(var Msg: TWMSetFocus);
begin
  inherited;
  {adjust the cursor position after exiting an embedded object}
  if ColumnHasObj then
    if Col < FieldCount then
      Col := Col + 1
    else begin
      Col := 1;
      Datasource.Dataset.Next;
    end;
end;

{______________________________________________________________________________}
procedure TjvclEDBGrid.WMGetDlgCode(var Msg: TWMGetDlgCode);
begin
  inherited;
  {set flag for KeyPress event (called once when entering each grid column)}
  ColumnHasObj := GetObjIndex(Col-1) <> -1;
end;

end.