Question

如何在选择后添加一个orderby？

//what I have now
string country_list = string.Join(":", ctx.Countries.Select(a => a.CountryName).ToArray());

return country_list;

//what I want to do, but the orderby doesnt see the projections
string country_list = string.Join(":", ctx.Countries.Select(a => a.CountryName).OrderBy(b => b.StateId).ToArray());

return country_list;

它与b的投影不起作用

Answer 1

您必须在OrderBy之前致电Select，因为在投影后，您尝试订购的列不再可用：

string country_list = string.Join(":", ctx.Countries.OrderBy(b => b.StateId).Select(a => a.CountryName).ToArray());

Answer 2

ctx.Countries.Select(a => new { a.CountryName, a.StateId })
             .OrderBy(b => b.StateId)
             .ToArray()

查询不为orderby投影？

2 个答案: