学步园

//
//                       使用说明：单击DBGridEh的标题栏排序（适用于ADO）
//            --在DBGridEh的事件OnTitleBtnClick引用该函数即可：
//               SortDBGridEh(Sender, ACol, Column);
//            --为了保证表格的每一列都能点击触发排序，你需要将你需要排序的列属性
//            --  Title->TitleButton设置为True。
//
procedure SortDBGridEh(Sender: TObject; ACol: Integer; Column: TColumnEh);
var
  FieldName, SortStr: string;
begin
  Screen.Cursor := crSQLWait;
  try
    if (Sender is TDBGridEh) and
      ((Sender as TDBGridEh).DataSource.DataSet <> nil) then
    begin
      if not ((Sender as TDBGridEh).DataSource.DataSet is
        TCustomADODataSet) then
        Exit;
      if not (Sender as TDBGridEh).DataSource.DataSet.Active then
        Exit;
      FieldName := Column.FieldName;
      if (Sender as
        TDBGridEh).DataSource.DataSet.FindField(FieldName).IsBlob then
        Exit;
      if (Sender as
        TDBGridEh).DataSource.DataSet.FieldByName(FieldName).FieldKind =
        fkData then
        SortStr := FieldName
      else if (Sender as
        TDBGridEh).DataSource.DataSet.FieldByName(FieldName).FieldKind =
        fkLookup then
        FieldName := (Sender as TDBGridEh).DataSource.DataSet.FieldByName
          (FieldName).KeyFields
      else
        FieldName := '';
      if (FieldName = '') or (Pos(';', FieldName) > 0) then
        Exit;
      case Column.Title.SortMarker of
        smNoneEh:
        begin
          Column.Title.SortMarker := smUpEh;
          TCustomADODataSet((Sender as
            TDBGridEh).DataSource.DataSet).Sort :=
            FieldName;
        end;
        smUpEh:
        begin
          Column.Title.SortMarker := smDownEh;
          TCustomADODataSet((Sender as
            TDBGridEh).DataSource.DataSet).Sort :=
            FieldName + ' DESC';
        end;
        smDownEh:
        begin
          Column.Title.SortMarker := smNoneEh;
          TCustomADODataSet((Sender as
            TDBGridEh).DataSource.DataSet).Sort := '';
        end;
      end;
    end;
  finally
    Screen.Cursor := crDefault;
  end;
end;