c# - 无法使用集合初始值设定项实现类型 XYZ，因为它不实现 'System.Collections.IEnumerable'

Question

我有以下类(class):

public class CommentList 
{
    string ItemType;
    string Comment1;
    string Status1;
    string DiscussionBoardId;
    Guid CourseId;
    Guid CommentID;
}

我正在尝试执行以下 LINQ 语句:

List<CommentList> query=
    from c in db.Comments
    join s in db.Status on c.StatusId equals s.StatusId
    join d in db.DiscussionBoards 
        on c.DiscussionBoardId equals d.DiscussionBoardId
    where d.CourseId=="CourseID"
    orderby d.ItemType, d.DiscussionBoardId
    select new CommentList {
        d.ItemType,
        c.Comment1,
        s.Status1,
        c.DiscussionBoardId,
        d.CourseId,
        c.CommentID
    };

问题是，编辑器在 select 语句的第一个括号上提示。它说:

Cannot implement type 'CommentList' with a collection initializer because it does not implement 'System.Collections.IEnumerable'.

有人可以帮助我并告诉我我做错了什么吗？

Answer 1

将您的字段公开，因为它们现在无法访问。

public class CommentList
{
  public string ItemType;
  public string Comment1;
  public string Status1;
  public string DiscussionBoardId;
  public Guid CourseId;
  public Guid CommentID;
}

并在您的初始化程序中明确设置它们。

select new CommentList
{
    ItemType = d.ItemType,
    Comment1 = c.Comment1,
    Status1 = s.Status1,
    DiscussionBoardId = c.DiscussionBoardId,
    CourseId = d.CourseId,
    CommentID = c.CommentID
};