How can I make a LINQ expression return into a class?

Question

I have the following LINQ:

        var questionIds = _questionsRepository.GetAll()
            .Where(m => m.Problem != null &&
            m.Problem.SubTopic != null &&
            m.Problem.SubTopic.Topic != null &&
            m.Problem.SubTopic.Topic.SubjectId == 1)
            .Select(m => m.QuestionId)
            .ToList();

Currently it does a select and returns a list of questionIds.

How can I change this LINQ so it returns a List

public class QuestionId
{
    public int QuestionId { get; set; }
}

Answer 1

创建一个QuestionId类的实例，并在Select内设置QuestionId属性，方法如下：

Select(m => new QuestionId { QuestionId = m.QuestionId })