SelectList根本不排序

Question

public static SelectList HolidayDays()
{
    SelectList retval = GenerateKeyValueList<HolidayCity>(HolidayCityHelper.GetFriendlyName, HolidayCity.NotSet);

    //sort
    retval.OrderBy(i => i.Text == "New York")
          .ThenBy(i => i.Text == "London")
          .ThenBy(i => i.Text);

    return retval;
}

为什么SelectList根本不排序呢？它的顺序与我甚至在执行排序操作之前的顺序完全相同，但它编译和运行时都没有错误。

Answer 1

OrderBy和ThenBy返回一个集合，您没有将其设置为返回值；

SelectList retval = GenerateKeyValueList<HolidayCity>(HolidayCityHelper.GetFriendlyName, HolidayCity.NotSet);

return new SelectList(retval
        .OrderByDescending(i => i.Text == "New York")
        .ThenByDescending(i => i.Text == "London")
        .ThenBy(i => i.Text).ToList(), 
    "Value", "Text");