查詢不投影oderby？

Question

如何在選擇後添加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; 

與B中的投影是心不是工作

Answer 1

你必須Select之前調用OrderBy，因爲投影后不再可用你試圖用命令列：

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()