IComparable CompareTo()，如何比较多个对象属性？

我正在尝试比较对象的多个属性，但我的代码只能比较程度属性。在 Visual Studio 中调试时，我的代码似乎完全缺少 else 语句。我将不胜感激任何提示。

class Student : IComparable 
{
    private string fName;
    private string lName;
    private string deg;
    private int gra;

    public Student(string firstName, string lastName, string degree, int grade)
    {
        fName = firstName;
        lName = lastName;
        deg = degree;
        gra = grade;
    }

    public override string ToString()
    {
        string var = lName + ", " + fName + " (" + deg + ") Grade: " + gra;
        return var;
    }

    public int CompareTo(object obj)
    {
        Student newStudent = obj as Student;

        if (this.deg.CompareTo(newStudent.deg) == 1)
        {
            return 1;
        }
        else if (this.deg.CompareTo(newStudent.deg) != 1)
        {
            return -1;
        }
        else //this is what my code is ignoring and not ordering by firstname as well
        {
            if (this.fName == newStudent.fName)
            {
                return 0;
            }
            else if (this.fName != newStudent.fName)
            {
                return -1;
            }
            else
            {
                return 0;
            }
        }
    }
}

首先回答你的问题（为什么else部分永远不会被执行）已经得到回答，也就是说，条件的第三种可能性是1 or not 1.

如果您尝试按不同的属性排序，例如，如果我们首先要按程度排序，然后按fName那么我们可以实现 IComparer-

class Student : IComparer<Student>{

    /*
    codes
   */


    public int Compare(Student student1, Student student2)
   {
          if(student1.deg.Equals(student2.deg))  //if both degrees are same
          {
              return string.Compare(student1.fName , student2.fName); // then compare fName
          }
          else
              return string.Compare(student1.deg , student2.deg);


   }
}