在JavaScript中获取asp.net控件的ID

Question

I am working in an ASP.Net application and need to get the ID of some client controls. I have tried the following but keep getting an error:

<script type="text/javascript">
    var cbDeclinedID = '<%= cbDeclined.ClientID %>';
</script>   

It does NOT matter where I put this code, I always get the error:

CS0103: The name 'cbDeclined' does not exist in the current context

The markup:

<%@ Page Title="Manage Resident Meals" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true" CodeBehind="ManageResidentMeals.aspx.cs" Inherits="Chart2GoWeb.WebUI.WebForms.ManageResident.ManageResidentMeals" %>

<asp:Content ID="jsContent" ContentPlaceHolderID="JavaScriptContent" runat="server">

<script type="text/javascript">
<!--
    // var cbDeclinedID = '< %= cbDeclined.ClientID % >';

    function NumericOnly() { var key = window.event.keyCode; if (key < 48 || key > 57) window.event.returnValue = false; }

    $(document).ready(function () {
        function UpdateTextBoxes(isDeclined, isNOP, isOutOfFac) {
            var ddlMealReplacement = $('#ddlMealReplacement');

            var lblMealOld = $('#lblMealOld');
            var lblFortifiedFluidOld = $('#lblFortifiedFluidOld');
            var lblFluidOld = $('#lblFluidOld');

            var txtMeal = $('#txtMeal');
            var txtFluid = $('#txtFluid');
            var txtFortifiedFluid = $('#txtFortifiedFluid');

            var mealReplacement = '';
            if (ddlMealReplacement.length) {
                mealReplacement = ddlMealReplacement.text();
            }

            if (isNOP || (isDeclined && mealReplacement != 'G')) {
                txtMeal.prop('disabled', true);
                txtMeal.val('');
                lblMealOld.val('___');
            } else {
                txtMeal.prop('disabled', false);
            }

            // txtFluid.Enabled = !isNOP;
            txtFluid.prop('disabled', isNOP);
            // txtFortifiedFluid.Enabled = !isNOP;
            txtFortifiedFluid.prop('disabled', isNOP);

            if (isNOP) {
                txtFluid.val('');
                txtFortifiedFluid.val('');
                $('#lblFluidTotalString').val('');
            }
        }

        function Total(lblFluidTotal, val1, val2) {
            var totalFluids = null;

            var num = parseFloat(val1);
            if (num != 'NaN')
                totalFluids = val1Num;

            num = parseFloat(val2);
            if (num != 'NaN')
                totalFluids = (totalFluids == null) ? num : num + totalFluids;

            if (totalFluids == null)
                lblFluidTotal.val('___');
            else
                lblFluidTotal.val(totalFluids);
        }

        $('#'+cbDeclinedID).click(function () {
            var cbDeclined = $(this);
            var cbIsOutOfFac = $('#cbIsOutOfFac');
            var cbNOP = $('#cbNOP');

            if (cbDeclined.is(':checked'))
                cbIsOutOfFac.attr('checked', false);

            UpdateTextBoxes(cbDeclined.is(':checked'), cbNOP.is(':checked'), cbIsOutOfFac.is(':checked'));
        });

        $('#cbIsOutOfFac').click(function () {
            var cbDeclined = $('#cbDeclined');
            var cbIsOutOfFac = $(this);
            var cbNOP = $('#cbNOP');

            UpdateTextBoxes(cbDeclined.is(':checked'), cbNOP.is(':checked'), cbIsOutOfFac.is(':checked'));
        });

        $('#cbNOP').click(function () {
            var cbDeclined = $('#cbDeclined');
            var cbIsOutOfFac = $('#cbIsOutOfFac');
            var cbNOP = $(this);

            UpdateTextBoxes(cbDeclined.is(':checked'), cbNOP.is(':checked'), cbIsOutOfFac.is(':checked'));
        });

        $('#ddlMealReplacement').change(function () {
            var cbDeclined = $('#cbDeclined');
            var cbIsOutOfFac = $('#cbIsOutOfFac');
            var cbNOP = $('#cbNOP');

            UpdateTextBoxes(cbDeclined.is(':checked'), cbNOP.is(':checked'), cbIsOutOfFac.is(':checked'));
        });

        $('#txtFluid').change(function () {
            var txtFluid = $(this);
            var txtFortifiedFluid = $('#txtFortifiedFluid');
            var lblFluidTotal = $('#lblFluidTotal');

            Total(lblFluidTotal, txtFluid.val(), txtFortifiedFluid.val());
        });

        $('#txtFortifiedFluid').change(function () {
            var txtFluid = $('#txtFluid');
            var txtFortifiedFluid = $(this);
            var lblFluidTotal = $('#lblFluidTotal');

            Total(lblFluidTotal, txtFluid.val(), txtFortifiedFluid.val());
        });
    });

    //-->
    </script> 

</asp:Content>

<asp:Content ID="Content1" ContentPlaceHolderID="HeadContent" runat="server">
</asp:Content>

<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">

    <asp:ObjectDataSource ID="ResidentsMealsODS" runat="server" 
        InsertMethod="InsertNourishment"        
        SelectMethod="GetMealsDetailByResMealInTakeId" 
        TypeName="Chart2GoWeb.Domain.DAL.ResidentsMealsDAL"
        UpdateMethod="UpdateNourishment"
        >

        <SelectParameters>
            <asp:SessionParameter DefaultValue="" Name="session" SessionField="__MySession__" Type="Object" />
            <asp:QueryStringParameter Name="resMealInTakeIdString" QueryStringField="resMealInTakeId" Type="String" />
            <asp:QueryStringParameter Name="nourishment" QueryStringField="nourishmentType" Type="String" />
        </SelectParameters>

        <InsertParameters>
            <asp:SessionParameter DefaultValue="" Name="session" SessionField="__MySession__" Type="Object" />
            <asp:QueryStringParameter Name="resMealInTakeIdString" QueryStringField="resMealInTakeId" Type="String" />
            <asp:QueryStringParameter Name="nourishment" QueryStringField="nourishmentType" Type="String" />
            <asp:Parameter Name="IsDeclined" Type="String"/>
            <asp:Parameter Name="IsOutOfFac" Type="String"/>
            <asp:Parameter Name="IsNpo" Type="String"/>
            <asp:Parameter Name="MealReplacement" Type="string"/>
            <asp:Parameter Name="Pct" Type="String"/>
            <asp:Parameter Name="Fluid" Type="String"/>
            <asp:Parameter Name="FortifiedFluid" Type="String"/>
            <asp:Parameter Name="FluidTotal" Type="String"/>
            <asp:Parameter Name="TubeFeeding" Type="String" />
        </InsertParameters>

        <UpdateParameters>
            <asp:SessionParameter DefaultValue="" Name="session" SessionField="__MySession__" Type="Object" />
            <asp:QueryStringParameter Name="resMealInTakeIdString" QueryStringField="resMealInTakeId" Type="String" />
            <asp:QueryStringParameter Name="nourishment" QueryStringField="nourishmentType" Type="String" />
            <asp:Parameter Name="IsDeclined" Type="String"/>
            <asp:Parameter Name="IsOutOfFac" Type="String"/>
            <asp:Parameter Name="IsNpo" Type="String"/>
            <asp:Parameter Name="MealReplacement" Type="String"/>
            <asp:Parameter Name="Pct2EditBind" Type="String"/>
            <asp:Parameter Name="Fluid2EditBind" Type="String"/>
            <asp:Parameter Name="FortifiedFluid2EditBind" Type="String"/>
            <asp:Parameter Name="TubeFeeding" Type="String" />
        </UpdateParameters>

    </asp:ObjectDataSource>

    <asp:ObjectDataSource ID="MealReplacementOptionDataSource" runat="server" 
        TypeName="Chart2GoWeb.Domain.Entities.WFEvents.MealReplacementOption" 
        SelectMethod="Select">
    </asp:ObjectDataSource>

    <asp:FormView
        DataSourceID="ResidentsMealsODS" 
        ID="nourishmentFormView" 
        DefaultMode="Edit" 
        OnItemInserted="nourishment_OnItemInserted" 
        OnItemUpdated="nourishment_OnItemUpdated" 
        RunAt="server">
        <EditItemTemplate>

        <table class="EventQtable">
            <tr>
                <th colspan="2">
                    <asp:Label ID="Title" runat="server"><% Response.Write( TitleString); %></asp:Label>
                </th>
            </tr>
            <tr>
                <td>Date</td>
                <td><asp:Label ID="mealDate" runat="server" Text='<%# Eval("MealDate") %>'/></td>
            </tr>
            <tr>
                <td>Declined</td>
                <td><asp:CheckBox ID="cbDeclined" runat="server" Checked='<%# Bind("IsDeclined") %>' /></td>
            </tr>
            <tr>
                <td>Out Of Facility</td>
                <td><asp:CheckBox ID="cbIsOutOfFac" runat="server" Checked='<%# Bind("IsOutOfFac") %>'/></td>
            </tr>
            <tr>
                <td>NPO</td>
                <td><asp:CheckBox ID="cbNPO" runat="server" Checked='<%# Bind("IsNpo") %>'/></td>
            </tr>
<% 
    // Only show the meal replacement if the nourishment type does NOT have an underscore in it.
    if (Request.QueryString["nourishmentType"].IndexOf('_') == -1)
    { 
%>
            <tr>
                <td>
                    Meal Replacement</td>
                <td>
                    <asp:DropDownList ID="ddlMealReplacement" runat="server" AutoPostBack="True" 
                        DataSourceID="MealReplacementOptionDataSource" DataTextField="DisplayValue" 
                        DataValueField="DBValue"                         
                        SelectedValue='<%# Bind("MealReplacement") %>' />
                </td>
            </tr>
<%
    }
%>
            <tr>
                <td>Meal</td>
                <td>
                    <asp:Label ID="lblMealOld" runat="server" CssClass="ccUnits" Text='<%# Eval("Pct4Edit") %>' />% +
                    <asp:TextBox ID="txtMeal" runat="server" type="number" CssClass="ccUnits" MaxLength="3" OnKeyPress="NumericOnly()" Text='<%# Bind("Pct2EditBind") %>' />%<asp:RangeValidator ID="rvRangeValidator" runat="server" ControlToValidate="txtMeal" ErrorMessage="Valid range is 0-200" MaximumValue="200" MinimumValue="0" Type="Integer">*</asp:RangeValidator>
                </td>
            </tr>
            <tr>
                <td>Fluid</td>
                <td>
                    <asp:Label ID="lblFluidOld" runat="server" CssClass="ccUnits" Text='<%# Eval("Fluid4Edit") %>' />cc +
                    <asp:TextBox ID="txtFluid" runat="server" type="number" CssClass="ccUnits" MaxLength="4" OnKeyPress="NumericOnly()" Text='<%# Bind("Fluid2EditBind") %>' />cc
                </td>
            </tr>
            <tr>
                <td>Fortified Fluid</td>
                <td>
                    <asp:Label ID="lblFortifiedFluidOld" runat="server" CssClass="ccUnits" Text='<%# Eval("FortifiedFluid4Edit") %>' />cc +
                    <asp:TextBox ID="txtFortifiedFluid" runat="server" type="number" CssClass="ccUnits" MaxLength="4" OnKeyPress="NumericOnly()" Text='<%# Bind("FortifiedFluid2EditBind") %>' />cc
                </td>
            </tr>
            <tr>
                <td>Fluid Total</td>
                <td>
                    <asp:Label ID="lblFluidTotal" runat="server" CssClass="ccUnits" Text='<%# Eval("FluidTotal4Edit") %>' />cc
                </td>
            </tr>
        </table>
        <asp:Button ID="saveButton" runat="server" CommandName="Update" CssClass="GenBtn" Text="Save" />&nbsp;
        <asp:Button ID="cancelButton" runat="server" CssClass="GenBtn" onclick="cancelButton_Click" Text="Cancel" />
        </EditItemTemplate>



        <InsertItemTemplate>
        <table class="EventQtable">
            <tr>
                <th colspan="2"><asp:Label ID="Title" runat="server"><% Response.Write( TitleString); %></asp:Label></th>
            </tr>
            <tr>
                <td>Date</td>
                <td><asp:Label ID="mealDate" runat="server" Text='<%# Eval("MealDate") %>'/></td>
            </tr>
            <tr>
                <td>Declined</td>
                <td><asp:CheckBox ID="cbDeclined" runat="server" Checked='<%# Bind("IsDeclined") %>'/></td>
            </tr>
            <tr>
                <td>Out Of Facility</td>
                <td><asp:CheckBox ID="cbIsOutOfFac" runat="server" Checked='<%# Bind("IsOutOfFac") %>'/></td>
            </tr>
            <tr>
                <td>NPO</td>
                <td><asp:CheckBox ID="cbNPO" runat="server" Checked='<%# Bind("IsNpo") %>'/></td>
            </tr>
<% 
    // Only show the meal replacement if the nourishment type does NOT have an underscore in it.
    if (Request.QueryString["nourishmentType"].IndexOf('_') == -1)
    { 
%>
            <tr>
                <td>Meal Replacement</td>
                <td><asp:DropDownList ID="ddlMealReplacement" runat="server" AutoPostBack="True" 
                                      DataSourceID="MealReplacementOptionDataSource" DataTextField="DisplayValue" 
                                      DataValueField="DBValue" 
                                      SelectedValue='<%# Bind("MealReplacement") %>' /></td>
            </tr>
<% 
    }
%>
            <tr>
                <td>Meal</td>
                <td>
                    <asp:Label ID="lblMealOld" runat="server" Text="0" CssClass="ccUnits"/>%&nbsp; +
                    <asp:TextBox ID="txtMeal" runat="server" type="number" Text='<%# Bind("Pct") %>' MaxLength="3" OnKeyPress="NumericOnly()" CssClass="ccUnits" />%<asp:RangeValidator ID="rvRangeValidator" runat="server" ErrorMessage="Valid range is 0-200" Type="Integer" MaximumValue="200" MinimumValue="0" ControlToValidate="txtMeal">*</asp:RangeValidator>
                </td>
            </tr>
            <tr>
                <td>Fluid</td>
                <td>
                    <asp:Label ID="lblFluidOld" runat="server" Text="0" CssClass="ccUnits"/>cc +
                    <asp:TextBox ID="txtFluid" runat="server" type="number" Text='<%# Bind("Fluid") %>' MaxLength="4" OnKeyPress="NumericOnly()" CssClass="ccUnits" />cc
                </td>
            </tr>
            <tr>
                <td>Fortified Fluid</td>
                <td>
                    <asp:Label ID="lblFortifiedFluidOld" runat="server" Text="0" CssClass="ccUnits" Enabled="false" />cc +
                    <asp:TextBox ID="txtFortifiedFluid" runat="server" type="number" Text='<%# Bind("FortifiedFluid") %>'  MaxLength="4" OnKeyPress="NumericOnly()" CssClass="ccUnits" />cc
                </td>
            </tr>
            <tr>
                <td>Fluid Total</td>
                <td>
                    <asp:Label ID="lblFluidTotal" runat="server" Text='0' CssClass="ccUnits"/>cc
                </td>
            </tr>
        </table>
        <asp:Button ID="saveButton"  CssClass="GenBtn" runat="server" Text="Save" CommandName="Insert"/>&nbsp;
        <asp:Button ID="cancelButton" CssClass="GenBtn" runat="server" Text="Cancel" onclick="cancelButton_Click"/>

        </InsertItemTemplate>
    </asp:FormView>

<script type="text/javascript">
    var cbDeclinedID = '<%= cbDeclined.ClientID %>';
</script> 

</asp:Content>

<asp:Content ID="Content3" ContentPlaceHolderID="FooterContent" runat="server"> 
    <table class="footer" border="0" cellspacing="0" cellpadding="0" style="background-image: url('<%= ResolveClientUrl("~/Images/BottomBar-1000x42.png")%>'); background-repeat: no-repeat; height: 42px; width: 1000px;" >
        <tr>
            <td width="4%">&nbsp;</td>
            <td width="9%"></td>
            <td width="56%">&nbsp;</td>
            <td width="27%" align="center"/>
            <td width="4%"></td>
        </tr>
    </table>
</asp:Content>

Answer 1

It's because dbDeclines is defined within the templates of your <asp:FormView id="nourishmentFormView"> .

Try this instead (untested)...

<script type="text/javascript">
    var cbDeclinedID = '<%=nourishmentFormView.FindControl("cbDeclined").ClientID%>';
</script>   

Answer 2

Stupid question but does cbDeclined exist?

If it does, is it possibly in another control (ie gridview or listview) that would then require you to get the grid, then .GetChildControl() instead of directly referencing cbDeclined?

The way you are currently doing it is the correct way to reference a ID in ASP.NET (unless you use static guessable IDs but that breaks functionality where theres repetition of controls).

EDIT

After your updated code, you appear to be tryign to reference a control inside another control, you'll need to do something like

<script type="text/javascript">
    var cbDeclinedID = '<%= ((CheckBox)nourishmentFormView.FindControl("cbDeclined")).ClientID %>';
</script>