public class Person : IComparable {
         public Person() { }
         public Person(string name, string sex) {
             this.Name = name;
             this.Sex = sex;
         }
         public string Name;
         public string Sex;
 
         public override string ToString() {
             return this.Name + " " + this.Sex;
         }
         #region IComparable 成员
         public int CompareTo(object obj) {
             Person p = obj as Person;
             if (p == null) {
                 throw new NotImplementedException();
             }
             return this.Name.CompareTo(p.Name);
         }
         #endregion
     }

public class PersonComparer:IComparer {
 public PersonComparer() { }
 #region IComparer 成员
 public int Compare(object x, object y) {
 Person p1 = x as Person;
 Person p2 = y as Person;
 if (p1 == null || p2 == null) {
 throw new ArgumentException("Person为空");
 }
 return p1.Name.CompareTo(p2.Name);
 }
 #endregion
 }