再次修复combobox下拉背景颜色

2023年2月写的修复lazarus combobox的下拉列表在linux时没有高亮显示选中的item的问题,需然解决了显示问题,但下拉列表的颜色在银河麒麟是灰黑色,和应用的颜色明显不搭,想要win一样样式，如果要改变下拉背景颜色，可以按以下修改就可以，当然，如果不想用白色，可以改为想要的颜色。
打开lazarus/lcl/include/customcombobox.inc
按以下修改后重新编译就可以.

procedure TCustomComboBox.DrawItem(Index: Integer; ARect: TRect;
  State: TOwnerDrawState);
begin
  //TControlCanvas(FCanvas).UpdateTextFlags;
  if Assigned(FOnDrawItem) then
    FOnDrawItem(Self, Index, ARect, State)
  else
  begin
    if not (odBackgroundPainted in State) then
      FCanvas.FillRect(ARect);
    InternalDrawItem(Self, FCanvas, ARect, Items[Index])
  end;
end;

改该:

procedure TCustomComboBox.DrawItem(Index: Integer; ARect: TRect;
  State: TOwnerDrawState);
begin
  //TControlCanvas(FCanvas).UpdateTextFlags;
  //2022.05.28 LBZ
  {$ifdef linux}
  if (FDroppedDown) then
  begin
    if  (GetItemIndex=index)  then   //当为ItemIndex时高亮显示item
    begin
      FCanvas.Brush.Color := clHighlight;
      FCanvas.Font.Color :=  clHighlightText or clHighlight;
      State:=[odSelected];
    end
    Else
    begin
     if not (odBackgroundPainted in State) then
      FCanvas.Brush.Color := clWhite;//背景颜色
      State:=[odFocused];
    end;
    //FCanvas.Font.Color:= clMenuText;
  end;
  {$endif}
  //2022.05.28 LBZ
  if Assigned(FOnDrawItem) then
    FOnDrawItem(Self, Index, ARect, State)
  else
  begin
    if not (odBackgroundPainted in State) then
      FCanvas.FillRect(ARect);
    InternalDrawItem(Self, FCanvas, ARect, Items[Index])
  end;
end;

修改将下拉是用系统主题颜色的:

修改后,用自定的颜色(和win一样的颜色):

procedure TCustomComboBox.LMDrawListItem(var TheMessage : TLMDrawListItem);
begin
  with TheMessage.DrawListItemStruct^ do
  begin
    FCanvas.Handle := DC;
    if Font<>nil then
    begin
      FCanvas.Font := Font;
      FCanvas.Font.PixelsPerInch := Font.PixelsPerInch;
    end;
    if Brush<>nil then
      FCanvas.Brush := Brush;
    if (ItemID <> UINT(-1)) and (odSelected in ItemState) then
    begin
      FCanvas.Brush.Color :=clHighlight;
      FCanvas.Font.Color := clHighlightText;
    end;
    DrawItem(ItemID, Area, ItemState);
    if odFocused in ItemState then
      {DrawFocusRect(hDC, rcItem)};
    FCanvas.Handle := 0;
  end;
end;

改为

procedure TCustomComboBox.LMDrawListItem(var TheMessage : TLMDrawListItem);
begin
  with TheMessage.DrawListItemStruct^ do
  begin
    FCanvas.Handle := DC;
    if Font<>nil then
    begin
      FCanvas.Font := Font;
      FCanvas.Font.PixelsPerInch := Font.PixelsPerInch;
    end;
    if Brush<>nil then
      FCanvas.Brush := Brush;
    if (ItemID <> UINT(-1)) and (odSelected in ItemState) then
    begin
      FCanvas.Brush.Color :=clHighlight;
      FCanvas.Font.Color := clHighlightText;
      {$ifdef linux}
      FCanvas.FillRect(Area);
      ItemState:=[odBackgroundPainted];
      {$endif}
    end;
    DrawItem(ItemID, Area, ItemState);
    if odFocused in ItemState then
      {DrawFocusRect(hDC, rcItem)};
    FCanvas.Handle := 0;
  end;
end;