簡化了兩個查詢到一個與同類型的LINQ

Question

我有這樣的代碼：

var commentData = from o in quack.BlogComments 
        join u in quack.AdminUsers 
        on o.UserId equals u.AdminUserId 
        where blogid == o.BlogId 
        select new 
        { 
         o.Comment, 
         o.CommentDate, 
         u.FirstName, 
         u.LastName 
        }; 

var commentData2 = from o in quack.BlogComments 
        join u in quack.RegularUsers 
        on o.UserId equals u.RegularUserId 
        where blogid == o.BlogId 
        select new 
        { 
         o.Comment, 
         o.CommentDate, 
         u.FirstName, 
         u.LastName 
        }; 

var l = commentData.ToList(); 
l.AddRange(commentData2); 

正如你可以在上面看到我在做2不同的查詢到數據庫中，然後加在一起，以產生一個在gridview中使用單個列表。

我想要的只是使用1查詢到數據庫，並將導致這些表中的兩個相結合。

我該怎麼辦？有多個連接可能嗎？

Answer 1

你應該使用Concat：

var commentData = (from o in quack.BlogComments 
        join u in quack.AdminUsers 
        on o.UserId equals u.AdminUserId 
        where blogid == o.BlogId 
        select new 
        { 
         o.Comment, 
         o.CommentDate, 
         u.FirstName, 
         u.LastName 
        }).Concat(from o in quack.BlogComments 
          join u in quack.RegularUsers 
          on o.UserId equals u.RegularUserId 
          where blogid == o.BlogId 
          select new 
          { 
           o.Comment, 
           o.CommentDate, 
           u.FirstName, 
           u.LastName 
          }); 

var l = commentData.ToList();