var allLineData = http://www.mamicode.com/from ss in LinkToSQL.CadNozTable
                                      from tt in LinkToSQL.TasCom
                                      where tt.TasComID == ss.FK_TasComID && ss.FK_TasComID == ID
                                      select ss;
                    if (allLineData.FirstOrDefault() != null)
                        MessageBox.Show(allLineData.First().IsPlate.ToString());

其中allLineData必须剥掉一层才可以取得下面的属性值，此时应使用.first()方法。