如何執行LINQ查詢並進行選擇？

Question

我運行的是以下幾點：

var abc = new adminModel(); 
string text = abc.AnswerType.SingleOrDefault(s => s.Value == "2"); 
string text0 = abc.AnswerType.Single(s => s.Value == "2").Text; 
var text1 = (from a in abc.AnswerType 
    here a.Value == "2" 
    select a.Text).SingleOrDefault(); 

凡AnswerType看起來是這樣的：

public class adminModel 
{ 

    public IEnumerable<SelectListItem> AnswerType 
    { 
     get 
     { 
      return new[] 
       { 
        new SelectListItem { Value = "1", Text = "1 answer" }, 
        new SelectListItem { Value = "2", Text = "2 answers" }, 
        new SelectListItem { Value = "3", Text = "3 answers" }, 
        new SelectListItem { Value = "4", Text = "4 answers" }, 
        new SelectListItem { Value = "5", Text = "5 answers" }, 
        new SelectListItem { Value = "6", Text = "6 answers" }, 
        new SelectListItem { Value = "7", Text = "7 answers" }, 
       }; 
     } 
    } 

} 

但我得到一個錯誤消息說，「不能轉換SelectListItem串」。有沒有一種方法可以從SelectListItem中提取文本？

Answer 1

在你的代碼AnswerType.SingleOrDefault(s => s.Value == "2")將返回SelectedListItem實例，而不是string。

如果你需要得到文本查詢將是：

string text = AnswerType.Single(s => s.Value == "2").Text; 

或

string text = AnswerType 
    .Where(s => s.Value == "2") 
    .Select(arg => arg.Text) 
    .SingleOrDefault(); 

Answer 2

試試這個：

string text = AnswerType 
     .Where(s => s.Value == "2") 
     .Select(s=> s.Text) 
     .SingleOrDefault();