From the answer of zespri and I got this idea from this answer.
class Program
{
static void Main(string[] args)
{
DateTime t = DateTime.Now; //Your selected date from Calendar
t -= new TimeSpan((int)t.DayOfWeek, 0, 0, 0);
Console.WriteLine("\tstart: " + t.Date.ToShortDateString());
Console.WriteLine("\tend: " + t.Date.AddDays(7).ToShortDateString());
Console.WriteLine("\t" + new string('-', 25));
for (int i = 0; i < 7; i++)
{
var d = t.AddDays(i);
if (d.DayOfWeek >= DayOfWeek.Monday && d.DayOfWeek <= DayOfWeek.Friday) //Range: Monday to Friday
Console.WriteLine(d.DayOfWeek + " : " + d);
}
Console.ReadLine();
}
}