Hannes Preishuber

<runat="server">

Daten:

<asp:TextBox ID="TextBox2" runat="server"></asp:TextBox><atlas:UpdatePanel ID="UpdatePanel1"

runat="server">

<ContentTemplate>

Datum:<asp:TextBox ID="TextBox1" runat="server" Width="89px"></asp:TextBox>&nbsp;

<asp:ImageButton ID="ImageButton1" runat="server" OnClientClick="kal1.style.display ='block';" ImageUrl="~/images/kalender.gif"

Style="left: 144px; top: 111px" /><br />

<asp:Panel ID="pnlCalender" runat="server" Height="50px" Style="left: 72px; position: relative;

top: -1px;" Width="125px" Font-Names="arial" Font-Size="Small" BackColor="#C0C0FF"

BorderColor="Blue" BorderWidth="1px">

<asp:LinkButton ID="lnkPrev" runat="server" OnClick="lnkPrev_Click"><<</asp:LinkButton>

<asp:Label ID="lblTitle" runat="server" Text="Label"></asp:Label>

<asp:LinkButton ID="lnkNext" runat="server">>></asp:LinkButton>&nbsp; <a onclick="kal1.style.display='none'"

style="left: 137px; position: absolute; top: 0px">x</a>

<br />

<asp:Calendar ID="Calendar1" runat="server" BackColor="White" BorderColor="#3366CC"

BorderWidth="1px" CellPadding="1" DayNameFormat="Shortest" Font-Names="Verdana"

Font-Size="8pt" ForeColor="#003399" ShowDayHeader="false" ShowTitle="false" Height="150px"

Width="150px">

<SelectedDayStyle BackColor="#009999" Font-Bold="True" ForeColor="#CCFF99" />

<TodayDayStyle BackColor="#99CCCC" ForeColor="White" />

<SelectorStyle BackColor="#99CCCC" ForeColor="#336666" />

<WeekendDayStyle BackColor="#CCCCFF" />

<OtherMonthDayStyle ForeColor="#999999" />

<NextPrevStyle Font-Size="8pt" ForeColor="#CCCCFF" />

<DayHeaderStyle BackColor="#99CCCC" ForeColor="#336666" Height="1px" />

<TitleStyle BackColor="#003399" BorderColor="#3366CC" BorderWidth="1px" Font-Bold="True"

Font-Size="10pt" ForeColor="#CCCCFF" Height="10px" />

</asp:Calendar>

</asp:Panel>

</ContentTemplate>

</atlas:UpdatePanel>

</form>

Code

At startup the code creates a jscript which find the DIV element id in the dom. Cause this DIV can be nested , (eg master page) it is good practice to use the created asp.net clientid as argument for getelementbyid. (do not hardcode it)

Then the the panel (div) is set to display none. Dont do that in the declaration of the calendar control, cause this is renderd by every AJAX callback and so the visible state would be reseted. 

When the user select a day the event of the calendar is fired. At this point i had 2 options,

-fill the textbox on client side: con: must generate the the script with controlid and do coding, pro: can place textbox outside updatepanel

-fill textbox on serverside: con: overhead in callback for textbox, limitations in html design pro: easy to implement

i decided to use the second option  and implemented the 3rd needed line of code in the calendar event handler.