C# distinct()如果要比较引用对象的话需要重载,否则引用全部不同,毫无效果
https://www.itsvse.com/thread-4989-1-1.html
https://www.jb51.net/article/162602.htm
https://blog.csdn.net/shaopengfei/article/details/36426763
https://www.itsvse.com/thread-4989-1-1.html
https://www.jb51.net/article/162602.htm
https://blog.csdn.net/shaopengfei/article/details/36426763