Example:
.aspx code:
<asp:Calendar ID="calSearch" runat="server" Width="159" Height="136" BorderColor="#c59e9e"
BorderStyle="Solid" BackColor="#ffffff" BorderWidth="2px" NextPrevFormat="ShortMonth"
DayNameFormat="FirstLetter" SelectionMode="Day" Font-Size="7pt">
<TodayDayStyle ForeColor="White" BackColor="#7D4D41" />
<SelectedDayStyle ForeColor="White" BackColor="#7D4D41" />
<TitleStyle BackColor="#ffffff" BorderColor="Black" Font-Bold="True" />
<WeekendDayStyle BackColor="#F4F4ED" />
<DayHeaderStyle BackColor="#D8CAC6" Font-Bold="True" Font-Size="7pt" ForeColor="#303030" />
<OtherMonthDayStyle ForeColor="#155684" />
</asp:Calendar>
C# code:
calSearch.SelectedDate.ToString("MMMM, dd yyyy");