如何获取日期是星期几？

声明参数为 string PatchDate, int weekDay = 0;
//获取日期转换 DateTime patchDate =Convert.ToDateTime(PatchDate);
如果传过来参数为星期二，会直接跳到星期二执行并返回值，代码如下：
switch (patchDate.DayOfWeek)//获取实例所表示日期是星期几
{
case DayOfWeek.Monday://星期一
weekDay = 1;
break;
case DayOfWeek.Tuesday://星期二
weekDay = 2;
break;
case DayOfWeek.Wednesday://星期三
weekDay = 3;
break;
case DayOfWeek.Thursday://星期四
weekDay = 4;
break;
case DayOfWeek.Friday://星期五
weekDay = 5;
break;
case DayOfWeek.Saturday://星期六
weekDay = 6;
break;
case DayOfWeek.Sunday://星期日
weekDay = 7;
break;
}