linq - Join With List Collection -

i try write join linq query. it's raise syntax error. can do? need user's conversation messages.

/* conversations = header info c.users = list<applicationuser> */ public list<conversationmessage> getall(applicationuser user) {     var query = m in _db.conversationmessages         join c in _db.conversations on m.conversationid equals c.conversationid         join u in _db.users on c.users.contains(user)          select m; } 

it seems me should more this:

public list<conversationmessage> getall(applicationuser user) {     var query =         c in _db.conversations         c.users.contains(user)         join m in _db.conversationmessages on c.conversationid equals m.conversationid         select m;      return query.tolist(); }