private void SetDTPToLastMonday()
{
string aDay = dtpMonday.Value.DayOfWeek.ToString();
//create a time span object of one day
System.TimeSpan ad = new TimeSpan(1,0,0,0);
if(aDay != "Monday")
{
do
{
dtpMonday.Value = dtpMonday.Value.Subtract(ad);
aDay = dtpMonday.Value.DayOfWeek.ToString();
}while (aDay != "Monday");
}
}