The VirtualStringTree header has a 'Background' property but setting it to a different color does not change the color. I suspect the tree is rendered using Windows themes.
How can I set the color?
You can use property THeader.Background
but you'll have to exclude toThemeAware
from TreeOptions.PaintOptions
. That would turn off themes, as TLama already said in his comment above.
I recommend you to use the events OnAdvancedHeaderDraw
and OnHeaderDrawQueryElements
. hoOwnerDraw
has to be included in Header.Options
for them to take effect.
In OnHeaderDrawQueryElements
you set Elements
to (at least) [hpeBackground]
and in OnAdvancedHeaderDraw
you do the custom drawing.
See this example (source):
procedure TfrmMain.MyVSTHeaderDrawQueryElements(Sender: TVTHeader;
var PaintInfo: THeaderPaintInfo; var Elements: THeaderPaintElements);
begin
Elements := [hpeBackground];
end;
procedure TfrmMain.MyVSTAdvancedHeaderDraw(Sender: TVTHeader;
var PaintInfo: THeaderPaintInfo; const Elements: THeaderPaintElements);
begin
if hpeBackground in Elements then
begin
PaintInfo.TargetCanvas.Brush.Color := clFuchsia; // <-- your color here
if Assigned(PaintInfo.Column) then
DrawFrameControl(PaintInfo.TargetCanvas.Handle, PaintInfo.PaintRectangle, DFC_BUTTON, DFCS_FLAT or DFCS_ADJUSTRECT); // <-- I think, that this keeps the style of the header background, but I'm not sure about that
PaintInfo.TargetCanvas.FillRect(PaintInfo.PaintRectangle);
end;
end;
procedure TfrmDepositDefrayalSingly.vstItemsManuallyHeaderDrawQueryElements(Sender: TVTHeader;
var PaintInfo: THeaderPaintInfo; var Elements: THeaderPaintElements);
begin
Elements := [hpeBackground];
end;
procedure TfrmDepositDefrayalSingly.vstItemsManuallyAdvancedHeaderDraw(Sender: TVTHeader;
var PaintInfo: THeaderPaintInfo; const Elements: THeaderPaintElements);
begin
if hpeBackground in Elements then
begin
PaintInfo.TargetCanvas.Brush.Color := cGlobalVar.BasicColor;
PaintInfo.TargetCanvas.FillRect(PaintInfo.PaintRectangle);
if Assigned(PaintInfo.Column) then
begin
PaintInfo.TargetCanvas.Brush.Color := clGray;
PaintInfo.TargetCanvas.FrameRect(PaintInfo.PaintRectangle);
end;
end;
end;
来源:https://stackoverflow.com/questions/32396875/how-to-set-the-color-of-virtualstringtree-header