// do something here

while (processDate.DayOfWeek != DayOfWeek.Monday)
    processDate = processDate.AddDays(-1);
 
string mondayDate = processDate.ToShortDateString();
 
while (processDate.DayOfWeek != DayOfWeek.Friday)
    processDate = processDate.AddDays(1);
 
string fridayDate = processDate.ToShortDateString();