C#时间 查询 上个月最后一天的时间
textBox1.Text = Convert.ToDateTime(DateTime.Now.AddDays(1 - DateTime.Now.Day).AddDays(-1).ToLongDateString()).ToString("yyyy-MM-dd 23:59:59");
textBox1.Text = Convert.ToDateTime(DateTime.Now.AddDays(1 - DateTime.Now.Day).AddDays(-1).ToLongDateString()).ToString("yyyy-MM-dd 23:59:59");