public void GetIndex() { var students = new Student[] { new Student { No = 1, Name = "李1", Score = 22.1 }, new Student { No = 2, Name = "李2", Score = 32.3 }, new Student { No = 3, Name = "李3", Score = 42.5 } }; var sqList = new SequenceList <Student>(students); var index = sqList.GetIndex(students[1]); }