C # datetime date plus 1 days minus one month minus one month, etc method

2. Today
4. DateTime.Now.Date.ToShortDateString ();
6. Yesterday, it was today's date minus one.
8. DateTime.Now.AddDays (-1). ToShortDateString ();
10. Tomorrow, in the same vein, add a
12. DateTime.Now.AddDays (1). ToShortDateString ();
16. This week, knowing that the day of the week is the first day of the week and that the first day of the week is a few days ago, it is important to note that every week here is from Sunday to Saturday
18. DateTime.Now.AddDays (Convert.todouble (0-convert.toint16 (DateTime.Now.DayOfWeek))). ToShortDateString ();
20. DateTime.Now.AddDays (Convert.todouble (6-convert.toint16 (DateTime.Now.DayOfWeek))). ToShortDateString ();
22. If you do not understand, then look at the Chinese display of the day of the week should understand the method
24. Since DayOfWeek returns the number of days of the week, we want to convert it into Chinese characters to facilitate our reading, some people may use switch to a control, in fact, not so troublesome
26. string[] Day = new string[] { "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"};
28. Day[convert.toint16 (DateTime.Now.DayOfWeek)];
32. Last week, the same thing, a week is 7 days, last week is this week minus 7 days, and next week is the same
34. DateTime.Now.AddDays (Convert.todouble (0-convert.toint16 (DateTime.Now.DayOfWeek))-7). ToShortDateString ();
36. DateTime.Now.AddDays (Convert.todouble (6-convert.toint16 (DateTime.Now.DayOfWeek))-7). ToShortDateString ();
38. Next week
40. DateTime.Now.AddDays (Convert.todouble ((0-convert.toint16 (DateTime.Now.DayOfWeek)) + 7). ToShortDateString ();
42. DateTime.Now.AddDays (Convert.todouble ((6-convert.toint16 (DateTime.Now.DayOfWeek)) + 7). ToShortDateString ();
44. This month, many people will say that the first day of this month is definitely number 1th, and the last day is the next month minus another day. Of course it's right.
46. The general wording
48. DateTime.Now.Year.ToString () + DateTime.Now.Month.ToString () + "1"; //First day
50. DateTime.Parse (DateTime.Now.Year.ToString () + DateTime.Now.Month.ToString () + "1"). AddMonths (1). AddDays (-1). ToShortDateString (); //Last day
54. It's easier to use ToString's character formatting in C #
56. DateTime.Now.ToString ("yyyy-mm-01");
58. DateTime.Parse (DateTime.Now.ToString ("yyyy-mm-01")). AddMonths (1). AddDays (-1).   ToShortDateString ();
62. Last month, minus one month
64. DateTime.Parse (DateTime.Now.ToString ("yyyy-mm-01")). AddMonths (-1).   ToShortDateString ();
66. DateTime.Parse (DateTime.Now.ToString ("yyyy-mm-01")). AddDays (-1).   ToShortDateString ();
68. Next month, add a month.
70. DateTime.Parse (DateTime.Now.ToString ("yyyy-mm-01")). AddMonths (1).   ToShortDateString ();
72. DateTime.Parse (DateTime.Now.ToString ("yyyy-mm-01")). AddMonths (2). AddDays (-1).   ToShortDateString ();
74. After 7 days
76. DateTime.Now.Date.ToShortDateString ();
78. DateTime.Now.AddDays (7). ToShortDateString ();
80. 7 days ago
82. DateTime.Now.AddDays (-7). ToShortDateString ();
84. DateTime.Now.Date.ToShortDateString ();
88. This year, formatting with ToString's characters makes it easy to figure out the first and last day of the year
90. DateTime.Parse (DateTime.Now.ToString ("yyyy-01-01")).   ToShortDateString ();
92. DateTime.Parse (DateTime.Now.ToString ("yyyy-01-01")). AddYears (1). AddDays (-1).   ToShortDateString ();
94. Last year, no more explaining.
96. DateTime.Parse (DateTime.Now.ToString ("yyyy-01-01")). AddYears (-1).   ToShortDateString ();
98. DateTime.Parse (DateTime.Now.ToString ("yyyy-01-01")). AddDays (-1).   ToShortDateString ();
100. Next year
102. DateTime.Parse (DateTime.Now.ToString ("yyyy-01-01")). AddYears (1).   ToShortDateString ();
104. DateTime.Parse (DateTime.Now.ToString ("yyyy-01-01")). AddYears (2). AddDays (-1).   ToShortDateString ();
108. This quarter, many people will feel the difficulty here, need to write a long process to judge. In fact, we all know that four quarters a year, three months a quarter
110. First we push the date to the first month of the quarter, and then the first day of the month is the first day of the quarter.
112. DateTime.Now.AddMonths (0-((datetime.now.month-1)% 3)).   ToString ("yyyy-mm-01");
114. Similarly, the last day of the quarter is the first day of the next quarter minus one
116. DateTime.Parse (DateTime.Now.AddMonths (3-((datetime.now.month-1)% 3)). ToString ("yyyy-mm-01")). AddDays (-1).   ToShortDateString ();
118. Next quarter, I believe you all know .... Call it
120. DateTime.Now.AddMonths (3-((datetime.now.month-1)% 3)).   ToString ("yyyy-mm-01");
122. DateTime.Parse (DateTime.Now.AddMonths (6-((datetime.now.month-1)% 3)). ToString ("yyyy-mm-01")). AddDays (-1).   ToShortDateString ();
124. Last quarter
126. DateTime.Now.AddMonths ( -3-((datetime.now.month-1)% 3)).   ToString ("yyyy-mm-01");
128. DateTime.Parse (DateTime.Now.AddMonths (0-((datetime.now.month-1)% 3)). ToString ("yyyy-mm-01")). AddDays (-1).  ToShortDateString ();

C # datetime date plus 1 days minus one day plus month minus one month etc method (turn)