c# - 比较系统日期和日期时间

Question

我正在使用下面的代码来比较两个时间：

DateTime systemtime = DateTime.Now;
DateTime timestart = Convert.ToDateTime(txtTimestart.Text);
DateTime timeend = Convert.ToDateTime(txtTimeend.Text);

if (systemtime < timestart || systemtime > timeend)
{
    MessageBox.Show("not auth.");
}
else
{
    MessageBox.Show("auth.");
}

但我也想比较当天。例如，如果今天是星期一或星期四，则用户已通过身份验证，否则不会。我该怎么做？谢谢。

Answer 1

DateTime systemtime = DateTime.Now;
if(systemtime.DayOfWeek == DayOfWeek.Monday)
{
...
}

Answer 2

timestart.DayOfWeek会给你诸如DayOfWeek.Thursday或之类的值DayOfWeek.Friday。

有关文档和示例，请参见此处：http: //msdn.microsoft.com/en-us/library/system.datetime.dayofweek.aspx

Answer 3

该DateTime对象将具有一个属性DayOfWeek。你可以只比较字符串。

Answer 4

试试这个

var systemtime = DateTime.Now;
var start = "Monday";
var finish = "Wednesday";
DayOfWeek startDay;
if (!Enum.TryParse<DayOfWeek>(start ,out startDay))
{
    //handle parse error 
}
DayOfWeek finishDay;
if (!Enum.TryParse<DayOfWeek>(finish, out finishDay))
{
    //handle parse error
}

if (systemtime.DayOfWeek < startDay || systemtime.DayOfWeek > finishDay)
{
    MessageBox.Show("not auth.");
}
else
{
    MessageBox.Show("auth.");
}