List.Sort（）引发mscorlib.dll中发生类型为'System.InvalidOperationException'的未处理异常-C＃

Question

I have a Person type list and it has some items and I want to sort this list by default(without any params). So I have used person.Sort() method. When I execute the code I get an exception writes

An unhandled exception of type 'System.InvalidOperationException' occurred in mscorlib.dll

at Sort() method. Any experts please explain the reason behind.

List<Person> person = new List<Person>();
person.Add(new Person() { Name = "crank arm", Age = 1234 });
person.Add(new Person() { Name = "chain ring", Age = 1334 });
person.Add(new Person() { Name = "regular seat", Age = 1434 });
person.Add(new Person() { Name = "banana seat", Age = 1444 });
person.Sort();

Answer 1

You need to make your Person class implement IComparable

The sort methods throws that exception when

The default comparer Comparer.Default cannot find an implementation of the IComparable generic interface or the IComparable interface for type T.

from MSDN

Answer 2

Person是您定义的类，Sort方法不知道如何在Person对象之间进行比较，您需要实现比较方法，您可以参考： http : //msdn.microsoft.com/zh-cn/library/3da4abas(v = vs.110）.aspx