使用LINQ使用Lambda表達式查詢IDictionary

Question

即使字典在調試時顯示正確的鍵/值對，它爲什麼不會返回正確的字符串？

IDictionary<string, string> states = 
        AFS.MvcApplication.UnitedStates.StateDictionary; 

string stateAbbrev = 
       states.Where(x => x.Key == State).Select(x => x.Value).ToString(); 

Answer 1

你想用FirstOrDefault代替ToString，因爲Select結果是IEnumerable<string>。這應該工作：

string stateAbbrev = states.Where(x => x.Key == State).Select(x => x.Value).FirstOrDefault(); 

Answer 2

你應該使用：

string stateAbbrev = states[State];