Question

I am using a modal popup extender which contains a panel having three textboxes and two buttons. I want to fill the textbox values with my specifications (the date selected)..but not getting it successfully.

protected void myCal_SelectionChanged(object sender, EventArgs e)
    {
        ModalPopupExtender1.Show();
        TextBoxStart.Text = myCal.SelectedDate.ToString();
        TextBoxEnd.Text = myCal.SelectedDate.ToString();
    }

Designer is

<asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Conditional" ChildrenAsTriggers="false">

  <ContentTemplate>        
      <asp:Calendar ID="myCal" runat="server" Height="600px" width="900px" 
        BorderColor="#F2F3F4" BorderWidth="3px" DayStyle-BorderWidth="1px" 
                TodayDayStyle-BackColor="#82CAFF" NextPrevFormat="ShortMonth" 
        SelectionMode="Day" DayHeaderStyle-Height="30px" 
                TitleStyle-BackColor="#CBE3F0" TitleStyle-ForeColor="#153E7E" 
        OtherMonthDayStyle-ForeColor="#B4CFEC" NextPrevStyle-ForeColor="#2554C7" 
        CssClass="mGrid" onselectionchanged="myCal_SelectionChanged">
        <DayHeaderStyle Height="30px" /><TitleStyle Height="50px" />
        <DayStyle BorderWidth="1px" HorizontalAlign="Left" VerticalAlign="Top" />
        <TodayDayStyle BackColor="#CBE3F0" />
    </asp:Calendar>

      <ajaxToolkit:ModalPopupExtender ID="ModalPopupExtender1" runat="server" TargetControlID="ButtonDummy" PopupControlID="pnlSelect">

      </ajaxToolkit:ModalPopupExtender>

</ContentTemplate>

      </asp:UpdatePanel>


    <asp:UpdatePanel ID="UpdatePanel2" runat="server" UpdateMode="Always">
<ContentTemplate>

       <asp:Panel ID="pnlSelect" runat="server" width="200px" Height="200px">

           <table border="0" cellspacing="6" cellpadding="0" style="background-color: white">
               <tr>
                   <td align="right"></td>
                   <td>
                       <h2>New Appointment</h2>
                   </td>
               </tr>
               <tr>
                   <td align="right">Start Date:</td>
                   <td>
                       <asp:TextBox ID="TextBoxStart" runat="server"></asp:TextBox></td>
               </tr>
               <tr>
                   <td align="right">End Date:</td>
                   <td>
                       <asp:TextBox ID="TextBoxEnd" runat="server"></asp:TextBox></td>
               </tr>
               <tr>
                   <td align="right">Name:</td>
                   <td>
                       <asp:TextBox ID="TextBoxName" runat="server"></asp:TextBox></td>
               </tr>
               <tr>
                   <td align="right"></td>
                   <td>
                       <asp:Button ID="ButtonOK" runat="server" OnClick="ButtonOK_Click" Text="OK" />
                       <asp:Button ID="ButtonCancel" runat="server" Text="Cancel" OnClick="ButtonCancel_Click" />
                   </td>
               </tr>
           </table>

       </asp:Panel>
    </ContentTemplate>

What can be wrong?

Answer 1

As these textboxes placed out of UpdatePanel they are not updated on async request. Place them into the same UpdatePanel or wrap by another one UpdatePanel and set UpdateMode to “Always” like below:

<asp:UpdatePanel runat="server" UpdateMode="Always">
    <ContentTemplate>
        <asp:Panel runat="server" ID="pnlSelect" >
            <asp:TextBox runat="server" ID="TextBoxStart" />
            <asp:TextBox runat="server" ID="TextBoxEnd" />
        </asp:Panel>
    </ContentTemplate>
</asp:UpdatePanel>

Try to set ChildrenAsTriggers property of the UpdatePanel1 to true or move ModalPopupExtender1 to UpdatePanel2.

Also, you can move PopupExtender and his target dummy button out of the UpdatePanel1 and swap pnlSelect with UpdatePanel2:

<asp:UpdatePanel runat="server" ID="UpdatePanel1" UpdateMode="Conditional" ChildrenAsTriggers="false">
    <ContentTemplate>
        <asp:Button ID="Button1" runat="server" Text="Click Me" />
    </ContentTemplate>
</asp:UpdatePanel>
<asp:Button ID="ButtonDummy" runat="server" Style="display: none" />
<ajaxToolkit:ModalPopupExtender ID="ModalPopupExtender1" runat="server" TargetControlID="ButtonDummy"
    PopupControlID="pnlSelect" BackgroundCssClass="modalBackground" />
<asp:Panel ID="pnlSelect" runat="server" Style="display: none" CssClass="modalPopup">
    <asp:UpdatePanel runat="server" ID="UpdatePanel2" UpdateMode="Always">
        <ContentTemplate>
            <asp:TextBox runat="server" ID="TextBoxStart" />
        </ContentTemplate>
    </asp:UpdatePanel>
</asp:Panel>