delphi: how can I put Image in DBGrid Title? - image

Question

How can I put Image in TDBGrid column heading?
I tried, but the image kept showing and kept disappearing when i put the mouse over the title.
procedure TForm1.DBGrid1DrawColumnCell(Sender: TObject; const Rect: TRect;
DataCol: Integer; Column: TColumn; State: TGridDrawState);
begin
if Column.FieldName = order then
Begin
Column.Title.Font.Color := clBlue;
//if gdFixed in State then // didn't work.. I don't know why!!!
if Rect.Top < 30 then
ImageList1.Draw(DBGrid1.Canvas, Rect.Right-18, Rect.Top-18, 0);
end
else
Column.Title.Font.Color := clWindowText;
end;

Answer 1

You can use a interposer class for TDBGrid and override the DrawCell procedure.
type
TDBGrid = Class(DBGrids.TDBGrid)
private
FIcon:TIcon;
FImageList: TImageList;
procedure SetImageList(const Value: TImageList);
Destructor Destroy;override;
published
procedure DrawCell(ACol, ARow: Longint; ARect: TRect; AState: TGridDrawState); override;
Property Imagelist: TImageList read FImageList Write SetImageList;
End;
TForm2 = class(TForm)
.......
implementation
{$R *.dfm}
{ TDBGrid }
destructor TDBGrid.Destroy;
begin
if Assigned(FIcon) then FIcon.Free;
inherited;
end;
procedure TDBGrid.SetImageList(const Value: TImageList);
begin
FImageList := Value;
FreeAndNil(FIcon);
if Assigned(FImageList) then
begin
FIcon := TIcon.Create;
FImageList.GetIcon(0, FIcon);
end;
end;
procedure TDBGrid.DrawCell(ACol, ARow: Integer; ARect: TRect; AState: TGridDrawState);
var
L_Col: Integer;
begin
if dgIndicator in Options then
L_Col := ACol - 1
else
L_Col := ACol;
inherited;
if Assigned(FIcon) and (L_Col > -1) and (ARow = 0) and (Columns[L_Col].FieldName = 'ID') and (gdFixed in AState) then
begin
Canvas.Draw(ARect.Right - 18, ARect.Bottom - 18, FIcon);
//FImagelist.Draw(Canvas,ARect.Right - 18, ARect.Bottom - 18,0); // would cause more flickering
end;
end;
procedure TForm2.FormCreate(Sender: TObject);
begin
DBGrid1.DoubleBuffered := true;
DBGrid1.Imagelist := ImageList1;
ReportMemoryLeaksOnShutDown := true;
end;