自定义比较方法IEqualityComparer的运用

今天在项目中就遇到一个这样的问题，当我把两个集合连接在一起并且想去除重复项时，利用.Distinct()无效，它出现的还是重复项。查了下资料，办法是自定义一个比较方法，如下：

List<Student> list = new List<Student>();
  Student a = new Student
  {
         UserId = 1,
         StudentName = "Eric"

  };
  Student b = new Student
  {
         UserId = 1,
         StudentName = "Eric"

  };

  Student c = new Student
  {
         UserId = 2,
         StudentName = "laoyi"

  };
  list.Add(a);
  list.Add(b);

  list.Add(c);
  var tt = list.Distinct(new StudentComparer());
 

public class Student
{
  public int UserId { get; set; }
  public string StudentName { get; set; }
}
 

自定义的比较类:
public class StudentComparer : IEqualityComparer<Student>
{
  public bool Equals(Student x, Student y)
  {
         return x.UserId.Equals(y.UserId);
  }

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

上述实例是排除ID相等的。