如何在TVirtualStringTree中填写滚动条上方的区域？

Question

我需要填写(黑色)我在下面的图片中突出显示的小白方块.

我试过添加额外的列.我试过扩展PaintInfo.PaintRectangle.我已经尝试了我能想到的Amount列上的每个设置.我没有想法.

任何人对如何做到这一点都有任何想法？

以下是执行自定义标题绘制的代码.(原谅with声明,不是我原来的代码....)

procedure TWinPOSReceiptPluginForm.ReceiptDisplayTreeAdvancedHeaderDraw(Sender: TVTHeader; var PaintInfo: THeaderPaintInfo;
  const Elements: THeaderPaintElements);
var
    TempText: string;
begin
    with PaintInfo do
    begin
      // First check the column member. If it is NoColumn then it's about the header background.

        if (hpeBackground in Elements) and (Column <> nil) then begin
          TempText := Column.Text;
          TargetCanvas.Brush.Color := $444444;
          TargetCanvas.FillRect(PaintRectangle);
          TargetCanvas.Font.Color := clWhite;
          TargetCanvas.Font.Style := [];
          TargetCanvas.TextOut (PaintRectangle.Left + 3, PaintRectangle.Top + 3, TempText);
          end;
    end;
end;

Answer 1

你的if条件错了.当hpeBackground在该区域的Elements中时永远不会成立,因为在这种情况下Column是nil.

由于Column nil检查只需要获取Column.Text,您需要更改该代码:

if hpeBackground in Elements then
begin
  if Column <> nil then
    TempText := Column.Text;
  TargetCanvas.Brush.Color := $444444;