public partial class Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
PreviousAssigmentCalendar.SelectedDate = DateTime.Today;
NewAssigmentCalendar.SelectedDate = DateTime.Today.AddDays(14);
projectEndCalendar.SelectedDate = DateTime.Today.AddDays(21);
}

}
protected void txtAssignSpy_Click(object sender, EventArgs e)
{
DateTime previousAssigment = PreviousAssigmentCalendar.SelectedDate;
DateTime newAssigment = NewAssigmentCalendar.SelectedDate;
DateTime endAssigment = projectEndCalendar.SelectedDate;
TimeSpan totalproject = newAssigment - previousAssigment;
int tassigmentproject = totalproject.Days;

if(tassigmentproject >= 14 && tassigmentproject < 21)
{
double projectcost = tassigmentproject * 500;
resultLabel.Text = "The spy " + CodeNameText.Text + " for assigment " + AssigmentNameText.Text +
String.Format("Total project cost is: {0:C}", projectcost);
}

else
{
resultLabel.Text = "At least 2 weeks between previous assigments and new assigment";
DateTime newAssigmentDate = PreviousAssigmentCalendar.SelectedDate.AddDays(14);
NewAssigmentCalendar.SelectedDate = newAssigmentDate;
NewAssigmentCalendar.VisibleDate = newAssigmentDate;
}

if(tassigmentproject >21)
{
double projectcost = (tassigmentproject * 500) + 1000;
resultLabel.Text = "The spy " + CodeNameText.Text + " for assigment " + AssigmentNameText.Text +
 String.Format("Total project cost is: {0:C}", projectcost);
}