unit jvDBGridMax;

interface

uses
  Windows, Messages, SysUtils, Classes, Controls, Grids, DBGrids,
  JvExDBGrids, JvDBGrid, Graphics;

type
  TTypeOrder = (oASC, oDESC, oNONE);



  TOrderStringList = class(TStringList)
  protected
    function GetAscending(Index: Integer): boolean;
    procedure SetAscending (Index: Integer; Value: boolean);
  public
    property Ascending[Index: Integer]: boolean read GetAscending write SetAscending;
  end;


  TNotifyReSort = procedure (Sender: TObject; ASortFields: TOrderStringList) of object;


  TColumnMax = class(TColumn)
  private
    { Private declarations }
    FOrdered: TTypeOrder;
  public
    { Public declarations }
    constructor Create(Collection: TCollection); override;
    destructor Destroy; override;
    property Ordered: TTypeOrder read FOrdered;
  published
    { Published declarations }
  end;


  TjvDBGridMax = class(TjvDBGrid)
  private
    { Private declarations }
    FShowOrderColor: boolean;
    FOrderColorAsc: TColor;
    FOrderColorDesc: TColor;
    FOnResort: TNotifyReSort;
    SortFields: TOrderStringList;
  protected
    { Protected declarations }
    function CreateColumns: TDBGridColumns; override;
    procedure DrawColumnCell(const Rect: TRect; DataCol: Integer;
      Column: TColumn; State: TGridDrawState); override;
    procedure TitleClick(Column: TColumn); override;      
  public
    { Public declarations }
    constructor Create(AOwner: TComponent); override;
  published
    { Published declarations }
    property ShowOrderColor: boolean read FShowOrderColor write FShowOrderColor;
    property OrderColorAsc: TColor read FOrderColorAsc write FOrderColorAsc;
    property OrderColorDesc: TColor read FOrderColorDesc write FOrderColorDesc;
    property OnResort: TNotifyReSort read FOnResort write FOnResort;
  end;

procedure Register;

implementation

procedure Register;
begin
  RegisterComponents('Max', [TjvDBGridMax]);
end;

{ TjvDBGridMax }

constructor TjvDBGridMax.Create(AOwner: TComponent);
begin
  inherited;
  SortFields := TOrderStringList.Create;

end;

function TjvDBGridMax.CreateColumns: TDBGridColumns;
begin
  Result := TDBGridColumns.Create(Self, TColumnMax);
end;

procedure TjvDBGridMax.DrawColumnCell(const Rect: TRect; DataCol: Integer;
  Column: TColumn; State: TGridDrawState);
begin
 
  


  
  //Deve essere per primo
  if Assigned(DataSource) then
  begin

    //Colora la colonna di ordinamento
    if FShowOrderColor then
    begin
      if (Assigned (Column.Field)) then
      begin
        if not HighlightCell(DataCol,DataLink.ActiveRecord,
          Column.Field.DisplayText,State) then
        begin

          if TColumnMax(Column).FOrdered = oDESC then
            Canvas.Brush.Color := FOrderColorDesc;

          if TColumnMax(Column).FOrdered = oASC then
            Canvas.Brush.Color := FOrderColorAsc;

          DefaultDrawColumnCell (Rect,DataCol,Column,State);
        end;

      end;
    end;
  end;

  inherited;

end;

procedure TjvDBGridMax.TitleClick(Column: TColumn);
Var
  aField: string;
  aFieldIndex: integer;
begin
  inherited;


  if Assigned(DataSource) then
  begin

    //Ordinamento ascendente/discendente
    case TColumnMax(Column).FOrdered of
    oNone : TColumnMax(Column).FOrdered := oASC;
    oASC  : TColumnMax(Column).FOrdered := oDESC;
    oDESC : TColumnMax(Column).FOrdered := oNONE;
    end;


    aField      := Column.FieldName;
    aFieldIndex := SortFields.IndexOf(aField);

    //Se non l'ho trovato lo aggiungo
    if aFieldIndex = -1 then begin
      SortFields.Add(aField);
      SortFields.Ascending[SortFields.Count - 1] := True;
      {
      Column.Field.DisplayLabel := Column.Title.Caption;
      Column.Title.Caption      := Column.Field.DisplayLabel + OrderStr[true];
      }
    end
    else begin
      //Altrimenti ordinamento al contrario
      SortFields.Ascending[aFieldIndex] := not SortFields.Ascending[aFieldIndex];

      if SortFields.Ascending[aFieldIndex] then
      begin
        SortFields.Delete(aFieldIndex);
        //Column.Title.Caption := Column.Field.DisplayLabel;

      end //se sono già in ordinamento discendente pulisco
      else begin
        //Column.Title.Caption := Column.Field.DisplayLabel +
        //  OrderStr[SortFields.Ascending[aFieldIndex]];
      end;
    end;

    if Assigned(FOnResort) then
      FOnResort(Self, SortFields);

    Invalidate;
  end;

end;

{ TColumnMax }

constructor TColumnMax.Create(Collection: TCollection);
begin
  inherited;
  FOrdered := oNone;
end;

destructor TColumnMax.Destroy;
begin

  inherited;
end;



{ TOrderStringList }

function TOrderStringList.GetAscending(Index: Integer): boolean;
begin
  Result := boolean(integer(Objects[Index]));
end;

procedure TOrderStringList.SetAscending(Index: Integer; Value: boolean);
begin
  Objects[Index] := pointer(integer(Value));
end;

end.