不好意思还得自己找原因
原因如下
procedure TCustomDBGrid.UpdateScrollBar;
var
SIOld, SINew: TScrollInfo;
begin
if FDatalink.Active and HandleAllocated then
with FDatalink.DataSet do
begin
SIOld.cbSize := sizeof(SIOld);
SIOld.fMask := SIF_ALL;
GetScrollInfo(Self.Handle, SB_VERT, SIOld);
SINew := SIOld;
if IsSequenced then
begin
SINew.nMin := 1;
SINew.nPage := Self.VisibleRowCount;
SINew.nMax := Integer(DWORD(RecordCount) + SINew.nPage - 1);
if State in [dsInactive, dsBrowse, dsEdit] then
SINew.nPos := RecNo; // else keep old pos
end
else
begin
SINew.nMin := 0;
SINew.nPage := 0;
SINew.nMax := 4;
if FDataLink.BOF then SINew.nPos := 0
else if FDataLink.EOF then SINew.nPos := 4
else SINew.nPos := 2;
end;
if (SINew.nMin <> SIOld.nMin) or (SINew.nMax <> SIOld.nMax) or
(SINew.nPage <> SIOld.nPage) or (SINew.nPos <> SIOld.nPos) then
SetScrollInfo(Self.Handle, SB_VERT, SINew, True);
end;
end;
//而issequenced中
function TCustomADODataSet.IsSequenced: Boolean;
begin
Result := Assigned(RecordSet) and Recordset.Supports(adApproxPosition) and
(CursorLocation <> clUseServer) and not Filtered;
end;