给你一句代码:
procedure TForm1.dxDBGrid1CustomDrawFooter(Sender: TObject;
ACanvas: TCanvas; ARect: TRect; ANode: TdxTreeListNode;
AColumn: TdxTreeListColumn; var AText: String; var AColor: TColor;
AFont: TFont; var AAlignment: TAlignment; var ADone: Boolean);
begin
if AColumn.Caption='CustNo' then
AText:=FloatToStr(StrToFloat(AText)+100.5);
end;
//其中100.5是你要在合计中增加的数量,'CustNo'是列标题。
//如果不加任何IF条件就可以在全部的列合计中加一个数