LINQ Union and Distinct

Question

我有一個C＃.Net網絡應用程序，我正在使用以下LINQ查詢獲取用戶創建的或用戶角色不同的建議清單。即使在Union和Distinct之後，要返回的列表也包含相同提案的模糊。我究竟做錯了什麼？

 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 class是什麼定義？您可能對Proposal類的默認相等運算符有問題。 As msdn says about Distinct：

通過使用默認的相等比較器對值進行比較返回序列不同元件。

編輯：換句話說，你有Equals和/或GetHashCode自定義實現？