c# - 修改 LINQ 输出 AnonymousType 无法赋值

Question

嗨，我有一个问题，我已经研究了好几个小时，但我一直收到错误

Property or indexer 'AnonymousType#1.XP' cannot be assigned to -- it is read only

问题出现在a.XP这里

    foreach (var a in comments)
    {
        a.XP = score.getLevel(a.XP);
    }

正如评论指出的那样，我从不说我想做什么，我想用改进后的值 score.getLevel(a.XP) 代替 a.XP。

完整代码如下

protected void GetComments()
{
    TimberManiacsDataContext db = new TimberManiacsDataContext();
    Score score = new Score();
    var comments = (from fComment in db.Comments
                    where fComment.PublishID == Convert.ToInt32(Request.QueryString["Article"])
                    orderby fComment.DateTime descending
                    select new
                    {
                        UserName = fComment.User.UserLogin.Username,
                        PostTime = fComment.DateTime,
                        UserImage = fComment.User.UserGeneralInfo.ProfilePicture,
                        Comment = fComment.Comment1,
                        UserID = fComment.UserID,
                        XP = fComment.User.CommunityScore
                    }).Take(10).ToList();

    foreach (var a in comments)
    {
        a.XP = score.getLevel(a.XP);
    }
    Commentlist.DataSource = comments;
    Commentlist.DataBind();
}

Answer 1

匿名类型的对象是只读的，但鉴于您的代码示例，几乎不需要在循环中尝试这种修改，只需将其作为查询执行的一部分即可。

XP = score.getLevel(fComment.User.CommunityScore)

如果您发现自己需要在查询执行后进行更改，那么您应该继续定义一个允许此类更改的类，然后选择该类而不是匿名类型。

class CommentData { ... } // define this type with your properties

// then use it for the query projection

select new CommentData 
{
    // ...
}