System.DateTime.Now.ToString("D"); //Tuesday, December 13, 2016
System.DateTime.Now.ToString("d");
//12/13/2016
System.DateTime.Now.ToString("F");
//Tuesday, December 13, 2016 4:53:52 PM
System.DateTime.Now.ToString("f"); //Tuesday, December 13, 2016 4:55 PM
System.DateTime.Now.ToString("G");
System.DateTime.Now.ToString(); // 12/13/2016 5:09:35 PM
System.DateTime.Now.ToString("g"); //12/13/2016 4:57 PM
System.DateTime.Now.ToString("T"); //4:57:56 PM
ystem.DateTime.Now.ToString("t"); //4:57PM
System.DateTime.Now.ToString("U"); //Tuesday, December 13, 2016 8:58:39 AM
System.DateTime.Now.ToString("u"); //2016-12-13 16:59:39Z
System.DateTime.Now.ToString("m"); //December 13
System.DateTime.Now.ToString("M");
System.DateTime.Now.ToString("r"); //Tue, 13 Dec 2016 17:01:20 GMT
System.DateTime.Now.ToString("R");
System.DateTime.Now.ToString("y"); //December, 2016
System.DateTime.Now.ToString("Y");
System.DateTime.Now.ToString("o"); //2016-12-13T17:02:24.1052667+08:00
System.DateTime.Now.ToString("O");
System.DateTime.Now.ToString("s"); //2016-12-13T17:02:59
System.DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss:ffff");
//2016-12-13 17:03:59:4871
System.DateTime.Now.ToString("yyyy年MM月dd HH时mm分ss秒");
// 2016年12月13 17时05分26秒