C# 显示本周日期

/// <summary>
/// 计算本周起始日期（礼拜一的日期）
/// </summary>
/// <param name="someDate">该周中任意一天</param>
/// <returns>返回礼拜一日期，后面的具体时、分、秒和传入值相等</returns>
public static DateTime CalculateFirstDateOfWeek(DateTime someDate)
{
int i = someDate.DayOfWeek - DayOfWeek.Monday;
if (i == -1) i = 6;// i值 > = 0 ，因为枚举原因，Sunday排在最前，此时Sunday-Monday=-1，必须+7=6。
TimeSpan ts = new TimeSpan(i, 0, 0, 0);
return someDate.Subtract(ts);
}
/// <summary>
/// 计算本周结束日期（礼拜日的日期）
/// </summary>
/// <param name="someDate">该周中任意一天</param>
/// <returns>返回礼拜日日期，后面的具体时、分、秒和传入值相等</returns>
public static DateTime CalculateLastDateOfWeek(DateTime someDate)
{
int i = someDate.DayOfWeek - DayOfWeek.Sunday;
if(i != 0) i = 7 - i;// 因为枚举原因，Sunday排在最前，相减间隔要被7减。
TimeSpan ts = new TimeSpan(i, 0, 0, 0);
return someDate.Add(ts);
}
/// <summary>
/// 判断选择的日期是否是本周（根据系统当前时间决定的‘本周’比较而言）
/// </summary>
/// <param name="someDate"></param>
/// <returns></returns>
public static bool IsThisWeek(DateTime someDate)
{
//得到someDate对应的周一
DateTime someMon = CalculateFirstDateOfWeek(someDate);
//得到本周一
DateTime nowMon = CalculateFirstDateOfWeek(DateTime.Now);
TimeSpan ts = someMon - nowMon;
if (ts.Days < 0)
ts = -ts;//取正
if (ts.Days >= 7)
{
return false;
}
else
{
return true;
}
}