//欲實現點擊DBGrid的Title對查詢結果排序，想作一個通用程序，不是一事一議，
//例如不能在SQL語句中增加Order by ...，因為SQL可能原來已經包含Order by ...，
//而且點擊另一個Title時又要另外排序，目的是想作到象資源管理器那樣隨心所欲。
PRocedure TfrmChild.DBGrid1TitleClick(Column: TColumn);
var
  SqlStr,myFieldName,TempStr: string;
  OrderPos: integer;
  SavedParams: TParams;
begin
  if not (Column.Field.FieldKind in [fkData,fkLookup]) then exit;
  if Column.Field.FieldKind =fkData then
    myFieldName := UpperCase(Column.Field.FieldName)
  else
    myFieldName := UpperCase(Column.Field.KeyFields);
  while Pos(myFieldName,';')<>0 do
    myFieldName := copy(myFieldName,1,Pos(myFieldName,';')-1)
                  + ',' + copy(myFieldName,Pos(myFieldName,';')+1,100);
  with TQuery(TDBGrid(Column.Grid).DataSource.DataSet) do
  begin
    SqlStr := UpperCase(Sql.Text);
//  if pos(myFieldName,SqlStr)=0 then exit;
    if ParamCount>0 then
    begin
      SavedParams := TParams.Create;
      SavedParams.Assign(Params);
    end;
    OrderPos := pos('ORDER',SqlStr);
    if (OrderPos=0) or
      (pos(myFieldName,copy(SqlStr,OrderPos,100))=0) then
      TempStr := ' Order By ' + myFieldName + ' Asc'
    else if pos('ASC',SqlStr)=0 then
      TempStr := ' Order By ' + myFieldName + ' Asc'
    else
      TempStr := ' Order By ' + myFieldName + ' Desc';
    if OrderPos<>0 then SqlStr := Copy(SqlStr,1,OrderPos-1);
    SqlStr := SqlStr + TempStr;
    Active := False;
    Sql.Clear;
    Sql.Text := SqlStr;
    if ParamCount>0 then
    begin
      Params.AssignValues(SavedParams);
      SavedParams.Free;
    end;
    Prepare;
    Open;
  end;