LINQ Union和Distinct

Question

我有一个C＃.Net网络应用程序，我使用以下LINQ查询来获取用户创建或具有各种用户角色的不同提案列表。即使在Union和Distinct之后，要返回的List也包含相同提案的dupes。我做错了什么？

      var thereturn = FindAll(DetachedCriteria.For<Proposal>(),
                             new Order("CreateDate", false));

     //get the proposals that aUser created
     IList<Proposal> it = 
                thereturn.Where(proposal => proposal.CreatedBy.Equals(aUser)).ToList();

     //get the proposals that aUser is a BOE Author
     IList<Proposal> it2 =
          thereturn.Where(proposal =>
              proposal.BOEs.Any(boe =>
                  boe.Users.Where(a => a.Name == aUser).Any())).ToList();
     //get all other proposals that aUser is on
     IList<Proposal> it3 = 
          thereturn.Where(proposal =>
              proposal.Users.Where(o => o.Name == aUser).Any()).ToList();
     //now union with all other proposals that aUser is on
     return it3.Union(it).Union(it2).
               OrderByDescending(o=>o.CreateDate).Distinct().ToList();

Answer 1

Proposal类的定义是什么？对于Proposal类，您的默认相等运算符可能存在问题。 As msdn says about Distinct：

  

通过使用默认的相等比较器来比较值，从序列返回不同的元素。

编辑：换句话说，您是否有Equals和/或GetHashCode的自定义实施？