C# 我需要有关此I.Score/I.Count的帮助。有一个错误无法隐式转换int？整型

看起来在您的模型类ArticleWithCore中，您没有声明属性Score为null，即int？相反，您声明了int。

谢谢您修复了它！

var v = (from a in dc.Articles
         join b in dc.ratings on a.ArticleID equals b.ArticleID into bb
         from b in bb.DefaultIfEmpty()
         group new { a, b } by new { a.ArticleID, a.Articletitle } into AA
         select new
         {
             AA.Key.ArticleID,
             AA.Key.Articletitle,
             Score = AA.Sum(a => a.b.Score) == null ? 0 : AA.Sum(a => a.b.Score),
             Count = AA.Count()
         }
         );

List<ArticlewithScore> AWS = new List<ArticlewithScore>();
foreach (var i in v)
{
    AWS.Add(new ArticlewithScore
    {
        ArticleID = i.ArticleID,
        ArticleTitle = i.Articletitle,
        Score = i.Score / i.Count
    });