查询一周内的CAML语句

public static string GetWeekCaml()
        {
           
            int weeknow = Convert.ToInt32(System.DateTime.Now.DayOfWeek);
            int daydiff = (-1) * weeknow;
            int dayadd = 6 - weeknow;
            DateTime dateBegin = System.DateTime.Now.AddDays(daydiff);
            DateTime dateEnd = System.DateTime.Now.AddDays(dayadd);
            string strDateBegin = SPUtility.CreateISO8601DateTimeFromSystemDateTime(dateBegin);
            string strDateEnd = SPUtility.CreateISO8601DateTimeFromSystemDateTime(dateEnd);

            string caml = @"<Where>
                             <And>
                              <Geq>
                                <FieldRef Name='Created' /><Value Type='DateTime'>{0}</Value>
                              </Geq>
                               <Leq>
                                <FieldRef Name='Created' /><Value Type='DateTime'>{1}</Value>
                              </Leq>
                             </And>
                          </Where>";
            caml = string.Format(caml,strDateBegin,strDateEnd);
            return caml;
        }