How to get the date of the next Sunday? [duplicate]

I use this extension method:

public static DateTime Next(this DateTime from, DayOfWeek dayOfWeek)
{
    int start = (int)from.DayOfWeek;
    int target = (int)dayOfWeek;
    if (target <= start)
        target += 7;
    return from.AddDays(target - start);
}