Develop Reference

ASP.Net C# - Multiple UpdateProgress controls on a page

I'm trying to implement UpdatePanels and UpdateProgress controls. I have two UpdatePanels that contain two different DropDownLists (ddlQuestion5IDs and ddlQuestion6IDs).
When I change the selected index of ddlQuestion6IDs, the UpdateProgress loads for both UpdatePanels/DropDownLists. Is this how they normally behave and is there a way of only displaying the corresponding UpdateProgress for each UpdatePanel?
<p>
<asp:UpdatePanel ID="UpdatePanel1" runat="server" ChildrenAsTriggers="false" UpdateMode="Conditional">
<ContentTemplate>
<asp:Label ID="Label6" runat="server" Text="Question 5:" Font-Bold="true"></asp:Label>
<br />
<asp:DropDownList ID="ddlQuestion5IDs" runat="server" OnSelectedIndexChanged="ddlQuestion5IDs_SelectedIndexChanged" AutoPostBack="true"></asp:DropDownList>
<asp:UpdateProgress ID="UpdateProgress1" runat="server" DynamicLayout="true">
<ProgressTemplate>
<img src="images/loader.gif" height="20" />
</ProgressTemplate>
</asp:UpdateProgress>
<br />
<asp:Label ID="Label19" runat="server" Text="Question type:" Font-Italic="true"></asp:Label>
<br />
<asp:Label ID="lblQuestion5Type" runat="server" Text=""></asp:Label>
<br /><br />
<asp:Label ID="Label22" runat="server" Text="Question:" Font-Italic="true"></asp:Label>
<br />
<asp:Label ID="lblQuestion5" runat="server" Text=""></asp:Label>
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="ddlQuestion5IDs" EventName="SelectedIndexChanged"/>
</Triggers>
</asp:UpdatePanel>
</p>
<p>
<asp:UpdatePanel ID="UpdatePanel2" runat="server" ChildrenAsTriggers="False" UpdateMode="Conditional">
<ContentTemplate>
<asp:Label ID="Label7" runat="server" Text="Question 6:" Font-Bold="true"></asp:Label>
<br />
<asp:DropDownList ID="ddlQuestion6IDs" runat="server" OnSelectedIndexChanged="ddlQuestion6IDs_SelectedIndexChanged" AutoPostBack="true"></asp:DropDownList>
<asp:UpdateProgress ID="UpdateProgress2" runat="server" DynamicLayout="true">
<ProgressTemplate>
<img src="images/loader.gif" height="20" />
</ProgressTemplate>
</asp:UpdateProgress>
<br />
<asp:Label ID="Label21" runat="server" Text="Question type:" Font-Italic="true"></asp:Label>
<br />
<asp:Label ID="lblQuestion6Type" runat="server" Text=""></asp:Label>
<br /><br />
<asp:Label ID="Label24" runat="server" Text="Question:" Font-Italic="true"></asp:Label>
<br />
<asp:Label ID="lblQuestion6" runat="server" Text=""></asp:Label>
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="ddlQuestion6IDs" EventName="SelectedIndexChanged"/>
</Triggers>
</asp:UpdatePanel>
</p>

By adding a AssociatedUpdatePanelID="UpdatePanelID" property to UpdateProgress

Change text in TextBox outside of UpdatePanel

I have a gridview inside an UpdatePanel (the gridview is showing in a popup). On click of a select button in that grid, I am trying to set a textbox text in the page. But its not working; if I remove the update panel then it will work.
This is my code in aspx:
<div><asp:TextBox ID="txt" runat="server /></div>
<asp:UpdatePanel ID="updLendersearch" runat="server" UpdateMode="Conditional">
<Triggers>
<asp:AsyncPostBackTrigger ControlID="btnLenderSearch" EventName="Click" />
</Triggers>
<ContentTemplate>
<div id="divLender" runat="server" class="white_content" style="height: 450px;top: 20%;width: 57%;">
<asp:Label ID="lblBenificiary" runat="server" Text="Beneficiary/Lender :" Font-Names="Candara" ></asp:Label>
<asp:TextBox ID="txtBeneficiaryName" Style="border: 1px solid red" runat="server" Width="80px" CssClass="txtboxes" Font-Names="Candara" ></asp:TextBox>
<asp:RequiredFieldValidator ID="reqBeneficiaryName" runat="server" ErrorMessage="*" ForeColor="Red" ControlToValidate="txtBeneficiaryName" ValidationGroup="lender"></asp:RequiredFieldValidator>
<asp:Label ID="lblLenderState" runat="server" Text="State :" Font-Names="Candara" ></asp:Label>
<asp:DropDownList ID="ddlLenderState" runat="server" AutoPostBack="true" Style="border: 1px solid red"
AppendDataBoundItems="true" CssClass="drpdown" OnSelectedIndexChanged="ddlLenderState_SelectedIndexChanged">
</asp:DropDownList>
<asp:RequiredFieldValidator ID="reqLenderState" runat="server" ErrorMessage="*" ForeColor="Red" ControlToValidate="ddlLenderState" ValidationGroup="lender"></asp:RequiredFieldValidator>
<asp:Label ID="lblLenderCity" runat="server" Text="City :" Font-Names="Candara" ></asp:Label>
<asp:DropDownList ID="ddlLenderCity" runat="server" Width="100px" AutoPostBack="true"
AppendDataBoundItems="true" CssClass="drpdown" OnSelectedIndexChanged="ddlLenderCity_SelectedIndexChanged">
</asp:DropDownList>
<asp:Label ID="lblBeneficiaryZip" runat="server" Text="Zip :" Font-Names="Candara" ></asp:Label>
<asp:DropDownList ID="ddlBeneficiaryZip" runat="server" AppendDataBoundItems="true" Width="100px"
AutoPostBack="true" CssClass="drpdown">
</asp:DropDownList>
<asp:Button ID="btnBenefeciary" ValidationGroup="lender" runat="server" Text="Search" Font-Names="Candara" CssClass="btnBenefeciary" OnClick="btnBenefeciary_Click"/>
<br><br><br><br>
<div>
<asp:GridView ID="grvLenderDetails" CssClass="GridViewStyle" ShowHeaderWhenEmpty="true" OnRowCommand="grvLenderDetails_RowCommand" runat="server" AutoGenerateColumns="false" AutoGenerateSelectButton="true">
<Columns>
.. .. ..
</Columns>
<EmptyDataTemplate>
No Records To Display
</EmptyDataTemplate>
</asp:GridView>
</div>
</div>
<div id="fadeLender" class="black_overlay" runat="server">
<asp:ImageButton ID="imgLenderClose" ImageUrl="../Images/closepnlbtn.png" runat="server"
align="right" Style="margin-right: 140px; margin-top: 78px; border: 0px" OnClick="imgLenderClose_Click" />
</div>
</ContentTemplate>
</asp:UpdatePanel>

If the TextBox is in another UpdatePanel. Make its UpdateMode Conditional which allows you to call its Update method programmatically.
protected void ddlLenderState_SelectedIndexChanged(object sender, GridViewSelectEventArgs e)
{
TxtInfo.Text = "Hello, i'm coming from the GridView.";
UpdInfo.Update();
}
Another approach would be to add an AsyncPostBackTrigger to the outer UpdatePanel with ControlID=grvLenderDetails and EventName=SelectedIndexChanged.
If it's not in an UpdatePanel, then you need to change that. Here are examples:
<asp:UpdatePanel runat="server" ID="UpdInfo" UpdateMode="Conditional">
<ContentTemplate>
<asp:TextBox ID="TxtInfo" runat="server />
</ContentTemplate>
</asp:UpdatePanel>
Here is the trigger approach that does not require you to call Update() from codebehind manually:
<asp:UpdatePanel runat="server" ID="UpdInfo" UpdateMode="Conditional">
<ContentTemplate>
<asp:TextBox ID="TxtInfo" runat="server />
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="grvLenderDetails" EventName="SelectedIndexChanged" />
</Triggers>
</asp:UpdatePanel>
Otherwise you'll need to use some sort of JS tricks, e.g.:
ScriptManager.RegisterStartupScript(this, GetType(), "ChangeTextBoxText", "<script type='text/javascript'>$('#"+txt.ClientId+"').val('Hello, i'm from the GridView');</script>", false);

First modalpopup in first panel does not open until second modalpopup opens in second panel

I have one updatepanel exists with two panels. Each panel have two buttons to open popup. I have two modalpopup & its target panels just below of two panels.Everything is working fine, but I am getting problem, if I click button in first panel then modalpopup does not open, but when I click button in second panel after click button in first panel then popup opens & viceversa.
I used following code:
<asp:UpdatePanel ID="up1" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<asp:Panel ID="pnl1" runat="server">
<asp:Button ID="btn1" runat="server" class="add-btn-1" Text="Add" />
</asp:Panel>
<asp:Panel ID="pnl2" runat="server">
<asp:Button ID="btn2" runat="server" class="add-btn-1" Text="Add" />
</asp:Panel>
<cc1:ModalPopupExtender ID="ModalPopup1" PopupControlID="pnlpopup1" TargetControlID="btn1"
BackgroundCssClass="modalBackground" runat="server" />
<asp:Panel runat="server" ID="pnlpopup1">
<%--code here--%>
</asp:Panel>
<cc1:ModalPopupExtender ID="ModalPopup2" PopupControlID="pnlpopup2" TargetControlID="btn2"
BackgroundCssClass="modalBackground" runat="server" />
<asp:Panel runat="server" ID="pnlpopup2">
<%--code here--%>
</asp:Panel>
</ContentTemplate>
What will be solution to solve this problem?
Thank you.

I executed your code and found no problems.It works.So post the code that you have given inside <%--code here--%>.I would also suggest that you add a OkControlID to your ModalPopupExtender.

<asp:UpdatePanel ID="up1" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<asp:Panel ID="pnl1" runat="server">
<asp:Button ID="btn1" runat="server" class="add-btn-1" Text="Add" />
</asp:Panel>
<asp:Panel ID="pnl2" runat="server">
<asp:Button ID="btn2" runat="server" class="add-btn-1" Text="Add" />
</asp:Panel>
<Ajax:ModalPopupExtender ID="ModalPopup1" PopupControlID="pnlpopup1" TargetControlID="btn1"
BackgroundCssClass="modalBackground" runat="server" />
<asp:Panel runat="server" ID="pnlpopup1" Style="width:400px;height:100px; background: gray;">
<table width="100%">
<tr>
<td align="left">
<asp:Label ID="lblheadinglunchout" Font-Underline="true" Text="First Popup"
runat="server" CssClass="labelPopup" Style="text-decoration: none"></asp:Label>
</td>
<td align="right">
<asp:ImageButton ID="imgbtnCancelPopUp" ImageUrl="Images/popupclose_button.png"
runat="server" Style="vertical-align: top;" CssClass="button" />
</td>
</tr>
</table>
</asp:Panel>
<Ajax:ModalPopupExtender ID="ModalPopup2" PopupControlID="pnlpopup2" TargetControlID="btn2"
BackgroundCssClass="modalBackground" runat="server" />
<asp:Panel runat="server" ID="pnlpopup2" Style="width:400px;height:100px; background: gray;">
<table width="100%">
<tr>
<td align="left">
<asp:Label ID="Label1" Font-Underline="true" Text="Secound Popup"
runat="server" CssClass="labelPopup" Style="text-decoration: none"></asp:Label>
</td>
<td align="right">
<asp:ImageButton ID="ImageButton1" ImageUrl="Images/popupclose_button.png"
runat="server" Style="vertical-align: top;" CssClass="button" />
</td>
</tr>
</table>
</asp:Panel>
</ContentTemplate>
</asp:UpdatePanel>

JavaScript not loading after partial update in ASP.Net

I have a problem with Javascript not load in asp.net when an updatepanel postback to the server and the problem is that javascript code is not in the same page where the updatepanel is so I can put it in pageLoad() function it is like this:
<script src="js/keyboard.js" type="text/javascript"></script>
and i use ASP.Net 4 and c# and this is my code code:
<link href="css/keyboard.css" rel="stylesheet" />
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<div style="text-align: left; padding-right: 140px">
<dx:aspxcombobox id="comboBoxLangauge" clientinstancename="comboboxLang"
cssclass="combo" runat="server" width="140px" clientidmode="Static">
<Items>
<dx:ListEditItem Text="English to Kurdish" Value="1" Selected="true" />
<dx:ListEditItem Text="Kurdish to English" Value="2" />
</Items>
<ClientSideEvents SelectedIndexChanged="IndexChanged" />
</dx:aspxcombobox>
</div>
<br />
<br />
<asp:Button ID="btnTranslate" runat="server" Text="Search" ClientIDMode="Static"
CssClass="Search" OnClick="btnTranslate_Click" />
<asp:TextBox ID="txtBoxWord" runat="server" ClientIDMode="Static"
class="keyboardInput Search" Style="width: 260px; direction: ltr"></asp:TextBox>
<asp:AutoCompleteExtender ID="autocom" ClientIDMode="Static" runat="server" CompletionSetCount="10"
EnableCaching="true" MinimumPrefixLength="1" TargetControlID="txtBoxWord" ServicePath="~/translator/AutoComplete.asmx" ServiceMethod="GetCompletionList">
</asp:AutoCompleteExtender>
<asp:RoundedCornersExtender ID="RoundedCornersExtender1" runat="server" TargetControlID="OutPanel"
Corners="All" Radius="5" BorderColor="Silver">
</asp:RoundedCornersExtender>
<br />
<br />
<div id="OutPanel" runat="server" clientidmode="Static" style="width: 440px; height: 200px; overflow: auto; margin-left: auto; margin-right: auto; padding-top: 10px;" visible="false">
</div>
</ContentTemplate>
</asp:UpdatePanel>
<div id="OutPanel" runat="server" clientidmode="Static" style="width:440px;height:200px;overflow:auto;margin-left:auto;margin-right:auto;padding-top:10px;" visible="false">
</div>
</ContentTemplate>
</asp:UpdatePanel>

"The problem is that javascript code is not in the same page where the updatepanel is"
Whereas make sure your JavaScript is available on the page with UpdatePanel to load it properly.

Combobox selected item is deleted once selected . Invalid Postback or Callback argument

I have four textboxes one combobox and one button ( and some other controls) in my page . Based on the values typed in the textboxes the related values are updated in the combobox. On clicking the submit button in my page It was giving the following error .
"Invalid postback or callback argument. Event validation is enabled using in configuration or in a page. For Secuity purposes,this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them. If the data is valid and expected . Use the ClientScriptManager.RegisterForEventsValidation method in order to register the postback or callback data for validation."
Now in the page directive I added
<%#Page EnableEentValidation="false">
When I type the values in the four textboxes the corresponding value will appear in the cobobox . But when I select that combobox value, the selected value wil be deleted . What is the reason for this ?
<%# Page Language="C#" MasterPageFile="~/Main.Master" AutoEventWireup="true" CodeBehind="AddeChecklist.aspx.cs"
Inherits="LabTrack.WebApplication.Echecklist.AddeChecklist" EnableEventValidation ="false" %>
<%# Register TagPrefix="Labinal" TagName="AutoCompleteControl" Src="~/UserControls/AutoCompleteEnabledWebUserControl.ascx" %>
<asp:Content ID="Content1" ContentPlaceHolderID="head" runat="Server">
<link href="../Styles/CheckListRev.css" rel="stylesheet" type="text/css" />
<!-- Style for the page -->
<link href="../Styles/AddeChecklist.css" rel="stylesheet" type="text/css" />
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="Server">
<asp:ScriptManager ID="ScriptManager1" EnablePartialRendering="true" runat="server">
</asp:ScriptManager>
<asp:Panel ID="ErrorMessagePanel" CssClass="ErrorPanel" Visible="true" runat="server">
<div class="ErrorDiv">
<asp:BulletedList CssClass="ErrorMessage" ID="ErrorMessageBulletedList" runat="server">
</asp:BulletedList>
</div>
</asp:Panel>
<div class="PageTitle">
<asp:Label ID="PageHeaderLabel" runat="server"></asp:Label>
</div>
<div class="MainDiv">
<div style="text-align: center;">
<div class="PlaceHolder">
<table id="formTable">
<tr>
<td>
<asp:UpdatePanel runat="server" ID="updatepanelCustomer" UpdateMode="Conditional">
<ContentTemplate>
<span class="boldLabelLong">Customer:</span><br />
<asp:TextBox ID="CustomerNameTextBox" Width="200" runat="server"></asp:TextBox>
<asp:HiddenField ID="IxCustomerHiddenField" runat="server" />
<asp:Button ID="customerTriggerbutton" runat="server" Text="Button" Style="display: none;" />
</ContentTemplate>
</asp:UpdatePanel>
</td>
<td>
<asp:UpdatePanel runat="server" ID="updatepanelProgram" UpdateMode="Conditional">
<ContentTemplate>
<span class="boldLabelLong">Program:</span><br />
<asp:TextBox ID="ProgramNameTextBox" Width="200" runat="server"></asp:TextBox>
<asp:Button ID="programTriggerbutton" runat="server" Text="Button" Style="display: none;" />
<asp:HiddenField ID="IxProgramHiddenField" runat="server" />
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="customerTriggerbutton" EventName="Click" />
</Triggers>
</asp:UpdatePanel>
</td>
<td>
<asp:UpdatePanel runat="server" ID="updatepanelWorkPackage" UpdateMode="Conditional">
<ContentTemplate>
<span class="boldLabelLong">WorkPackage:</span><br />
<asp:TextBox ID="WorkPackageNameTextBox" Width="200" runat="server"></asp:TextBox>
<asp:HiddenField ID="IxWorkPackageHiddenField" runat="server" />
<asp:Button ID="workPackageTriggerbutton" runat="server" Text="Button" Style="display: none;" />
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="programTriggerbutton" EventName="Click" />
</Triggers>
</asp:UpdatePanel>
</td>
<td>
<asp:UpdatePanel runat="server" ID="updatepanelActivity" UpdateMode="Conditional">
<ContentTemplate>
<span class="boldLabelLong">Activity:</span><br />
<asp:TextBox ID="ActivityNameTextBox" Width="200" runat="server"></asp:TextBox>
<asp:HiddenField ID="IxActivityHiddenField" runat="server" />
<asp:Button ID="activityTriggerbutton" runat="server" Text="Button" Style="display: none;" />
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="workPackageTriggerbutton" EventName="Click" />
<asp:AsyncPostBackTrigger ControlID="activityTriggerbutton" EventName="Click" />
</Triggers>
</asp:UpdatePanel>
</td>
</tr>
</table>
</div>
<div class="PlaceHolder">
<asp:Label ID="TemplateLabel" Text="Template:" CssClass="ControlLabel" runat="server"></asp:Label>
<asp:UpdatePanel runat="server" ID="updatepanelTemplate" UpdateMode="Conditional">
<ContentTemplate>
<asp:DropDownList ID="TemplateSelectDropDownList" runat="server" Width="400" Visible="true"
AutoPostBack="true">
</asp:DropDownList>
<asp:HiddenField ID="IxTemplateHiddenField" runat="server" />
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="workPackageTriggerbutton" EventName="Click" />
</Triggers>
</asp:UpdatePanel>
<asp:Panel ID="SustainPanelTemplateOwner" Visible="true" runat="server">
<div>
<asp:Label ID="TemplateOwnerLabel" Text="Owner:" CssClass="ControlLabel" runat="server"></asp:Label>
<asp:TextBox ID="TemplateOwnerTextBox" CssClass="controlMargin" Width="400" runat="server"></asp:TextBox>
</div>
</asp:Panel>
<asp:HiddenField ID="IxDeliverableHiddenField" runat="server" />
<asp:HiddenField ID="IxReleaseActionHiddenField" runat="server" />
<asp:HiddenField ID="IxConfigHiddenField" runat="server" />
<asp:HiddenField ID="IxTemplateOwnerHiddenField" runat="server" />
<asp:HiddenField ID="TemplateSelectedSnameHiddenField" runat="server" />
<asp:HiddenField ID="TemplateOwnerSelectedsNameHiddenField" runat="server" />
<asp:HiddenField ID="DeliverableSelectedHiddenField" runat="server" />
<div>
<asp:Label ID="DeliverableLabel" CssClass="ControlLabel" runat="server" Text="Deliverable:"></asp:Label>
<asp:TextBox ID="DeliverableTextBox" CssClass="controlMargin" Width="400" runat="server"></asp:TextBox>
</div>
<asp:Panel ID="SustainPanelConfig" Visible="true" runat="server">
<div>
<asp:Label ID="ConfigurationLabel" runat="server" Text="Configuration:" CssClass="ControlLabel"></asp:Label>
<select id="ConfigurationSelect" class="controlMargin">
<option></option>
</select>
</div>
</asp:Panel>
<asp:Panel ID="SustainPanelRelease" Visible="true" runat="server">
<div>
<asp:Label ID="ReleaseActionLabel" CssClass="ControlLabel" runat="server" Text="Release Action:"></asp:Label>
<asp:TextBox ID="ReleaseActionTextBox" CssClass="controlMargin" Width="400" runat="server"></asp:TextBox>
</div>
</asp:Panel>
<asp:Panel ID="SustainPanel" Visible="true" runat="server">
<div class="SustainPanelControls">
<div>
<asp:Label ID="ChangeLabel" Text="Change #: " runat="server"></asp:Label>
</div>
<div>
<asp:TextBox ID="ChangeTextBox" Width="110" runat="server"></asp:TextBox>
</div>
<div>
<asp:Label ID="SupplementLabel" Text="Supplement: " runat="server"></asp:Label>
</div>
<div>
<asp:TextBox ID="SupplementTextBox" Width="80" runat="server"></asp:TextBox>
</div>
<div>
<asp:Label ID="NewWrrLabel" Text="WRR #: " runat="server"></asp:Label>
</div>
<div>
<asp:TextBox ID="NewWrrTextBox" Width="80" runat="server"></asp:TextBox>
</div>
<div>
<asp:Label ID="DddLabel" Text="3D: " runat="server"></asp:Label>
</div>
<div>
<asp:TextBox ID="DddTextBox" Width="80" runat="server"></asp:TextBox>
</div>
</div>
<div>
<table id="DesignDataTable2">
<tr>
<td>
<asp:Label ID="AllFbSheetsWrrLabel" Text="All F/B Sheets w/WRR #:" CssClass="ControlLabel" runat="server"></asp:Label>
</td>
<td>
<asp:TextBox CssClass="completeControl" ID="AllFbSheetsWrrTextBox" Width="588" Rows="2"
TextMode="MultiLine" runat="server"></asp:TextBox>
</td>
</tr>
</table>
</div>
</asp:Panel>
</div>
<div class="EditButtonGroup">
<input id="EditButton" type="button" value="Edit" class="ButtonSettings" />
<input id="RemoveButton" type="button" value="-" class="ButtonSettings" />
<input id="AddButton" type="button" value="+" class="ButtonSettings" />
</div>
</div>
<div class="ViewData">
<div class="ViewDataDiv">
<table id="DesignDataTable" class="designDataTable">
<tbody>
</tbody>
</table>
</div>
</div>
<div class="submitButtonDiv">
<asp:Button ID="SubmitButton" runat="server" Text="Button Text" class="submitButtonCreateChecklist" />
</div>
</div>
</asp:Content>

You are creating new values on the client side, and posting them back to the server.
For security reasons ASP.NET implements "event validation". When even validation is enabled, if the server creates a combo with 3 possible values, it will only accept this values on postback. If you create a different value and send it back to the server, you get the error you're referring to.
Here you have some info:
Page.EnableEventValidation Property
You can use ClientScriptManager.RegisterForEventValidation Method if you know which are the possible values generated on the client side, or disable validation completely if you don't know them in advance.
To disable validation:
You set the EnableEventValidation property by setting the enableEventValidation attribute of the # Page directive or the enableEventValidation attribute of the pages element in the Web.config file. If you set this property in code, you must set it before the page is initialized.

Sounds like an issue with Viewstate overriding the values.
Try fetching the value directly using Request.Form[Dropdown.ClientId]