Displaying the Popup
By default the RadDatePicker control displays a button to the left of the input area. When the user clicks on the button, an embedded RadCalendar control pops up to aid in selecting a date. This behavior happens automatically, without any programming on your part.
You can alter this behavior, hiding the DatePopupButton on the RadDatePicker control and displaying the popup control via client-side code. The client-side showPopup() method displays the popup calendar control.
The following example illustrates how to hide the popup buttons and use client-side code to display the popup. The RadDatePicker control displays its popup when the input area gets focus. The RadTimePicker control displays its popup when the user clicks in the input area. The RadDateTimePicker control displays its popup in response to a user key press.
<asp:Label ID="Label1" runat="server"
AssociatedControlID="RadDatePicker1" Text="Date" />
<telerik:RadDatePicker RenderMode="Lightweight" ID="RadDatePicker1" runat="server">
<DateInput>
<ClientEvents OnFocus="ShowDatePopup" />
</DateInput>
<Calendar DayNameFormat="FirstLetter" FirstDayOfWeek="Default"
UseColumnHeadersAsSelectors="False"
UseRowHeadersAsSelectors="False">
</Calendar>
<DatePopupButton Visible="False" />
</telerik:RadDatePicker>
Note that the embedded DatePopupButton control has Visible property set to False. This hides the button that appears by default. On RadDatePicker, the OnFocus client event on the embedded RadDateInput control is used to display the popup.