•获取指定年月的第一天
1 public static DateTime GetCurMonthFirstDay(string year,string mon) 2 { 3 DateTime AssemblDate = Convert.ToDateTime(year + "-" + mon + "-" + "01"); // 组装当前指定月份 4 return AssemblDate.AddDays(1 - AssemblDate.Day); // 返回指定当前月份的第一天 5 }
调用
1 private void button1_Click(object sender, EventArgs e) 2 { 3 DateTime FirstDay = GetCurMonthFirstDay("2019","2"); // 2019-02-01 00:00:00 4 }
•获取指定年月的最后一天
1 public static DateTime GetCurMonthLastDay(string year, string mon) 2 { 3 DateTime AssemblDate = Convert.ToDateTime(year + "-" + mon + "-" + "01"); // 组装当前指定月份 4 return AssemblDate.AddDays(1 - AssemblDate.Day).AddMonths(1).AddDays(-1); // 返回指定当前月份的最后一天 5 }
调用
1 private void button1_Click(object sender, EventArgs e) 2 { 3 DateTime LastDay = GetCurMonthLastDay("2019", "2"); // 2019-02-28 00:00:00 4 }
•获取当前月的第一天
1 public static DateTime GetCurMonthFirstDay() 2 { 3 // 第一种写法 4 //DateTime CurDate =Convert.ToDateTime(DateTime.Now.ToString()); // 组装当前指定月份 5 //return CurDate.AddDays(1 - CurDate.Day); // 返回指定当前月份的第一天 6 7 // 第二种写法 8 DateTime nowDate = DateTime.Now; 9 return new DateTime(nowDate.Year, nowDate.Month, 1); // 该方法可以指定,年、月、日 10 }
调用
1 private void button1_Click(object sender, EventArgs e) 2 { 3 DateTime FirstDay = GetCurMonthFirstDay(); // 2019-02-01 00:00:00 4 }
•获取当前月的最后一天
1 public static DateTime GetCurMonthLastDay() 2 { 3 DateTime CurDate = Convert.ToDateTime(DateTime.Now.ToString()); // 组装当前指定月份 4 return CurDate.AddDays(1 - CurDate.Day).AddMonths(1).AddDays(-1); // 返回指定当前月份的最后一天 5 }
调用
1 private void button1_Click(object sender, EventArgs e) 2 { 3 DateTime LastDay = GetCurMonthLastDay(); // 2019-02-28 00:00:00 4 }
•其他
1 private void button1_Click(object sender, EventArgs e) 2 { 3 string year = DateTime.Now.Year.ToString(); // 获取年份;2019 4 string mon = DateTime.Now.Month.ToString(); // 获取月份;2 5 string week = DateTime.Now.DayOfWeek.ToString(); // 获取周几;Tuesday 6 string days = DateTime.Now.DayOfYear.ToString(); // 获取一年中的第几天;50 7 }