创建一个IQueryable列表是不同

Question

我有对象，GroupStudentStatus的名单，我需要做出不同的。 我写了下面这个类来做到这一点。
的2个属性是相关是GroupStudentStatus.IsLastActionRemoved（日期时间）和GroupStudentStatus.Student.Guid。

protected List<GroupStudentStatus> RemovedStudents 
{ 
    get 
    { 
     return AllStudents.Where(s => s.IsLastActionRemoved).Distinct().OrderByDescending(d => d.LastActionDate).ToList(); 
    } 
} 

public class GroupStudentStatusComparer : IEqualityComparer<GroupStudentStatus> 
{ 
    public GroupStudentStatus Compare(GroupStudentStatus x, GroupStudentStatus y) 
    { 
     //get the student that was last removed 
     if (!Equals(x, y)) 
     { 
      return x.LastActionDate > y.LastActionDate ? x : y; 
     } 

     return x; 
    } 
    public bool Equals(GroupStudentStatus x, GroupStudentStatus y) 
    { 
     return x.Student.Guid.Equals(y.Student.Guid); 
    } 

    public int GetHashCode(GroupStudentStatus obj) 
    { 
     return obj.Student.Guid.GetHashCode(); 
    } 


} 

我认为这是正确的，除了我不知道如何测试它。

我试图做到这一点：

return AllStudents.Where(s => s.IsLastActionRemoved) 
        .Distinct(new GroupStudentStatusComparer((x, y) => x.Compare(x,y))) 
        .OrderByDescending(d => d.LastActionDate).ToList(); 

Answer 1

return AllStudents.Where(s => s.IsLastActionRemoved) 
        .Distinct(new GroupStudentStatusComparer()) 
        .OrderByDescending(d => d.LastActionDate) 
        .ToList(); 

Answer 2

return AllStudents.Where(s => s.IsLastActionRemoved).GroupBy(gss => gss.Student).Select(g => new GroupStudentStatus(g.Key, g.Select(gss2 => gss2.LastActionDate).Max(), true)).OrderByDescending(d => d.LastActionDate).ToList(); 

结束了使用GROUPBY。