Use Fincontrol on an aspx form using c#

I am trying to use FindControl on aspx form using c#.  My code is as follows and FinControl returns null.  Thanks

<%@ Page Language="C#" MasterPageFile="~/Site1.Master" AutoEventWireup="true" Theme="Default" CodeBehind="Default.aspx.cs" Inherits="Application.Web.Default" Title="Information Database" %>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="server">
<table width="100%">
        <tr>
            <td>
               <div  ><asp:LinkButton Text="Clear" ID="ClearButton1" CssClass="clearButton" runat="server" OnClick="ClearButton_Onclick" CommandArgument="OfficeList"></asp:LinkButton></div>
            </td>

        protected void ClearButton_Onclick(object sender, EventArgs e)
        {//CommandArgument contains name of control to be found.
            LinkButton lb = sender as LinkButton;
             ListBox List = (ListBox)FindControl(lb.CommandArgument);
            List.SelectedIndex = -1;
LVL 3
eshurakAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

JunkManCommented:
If the control "OfficeLis" being added progamatically or does it exist on the page?
0
JunkManCommented:
sorry typo there, meant "OfficeList"
0
Anurag ThakurTechnical ManagerCommented:
you cannot find a control by using the commandargument

if you use lb.ID you will be able to find your control and later you can use your command argument to take a decision what has to be done
0
Cloud Class® Course: Certified Penetration Testing

This CPTE Certified Penetration Testing Engineer course covers everything you need to know about becoming a Certified Penetration Testing Engineer. Career Path: Professional roles include Ethical Hackers, Security Consultants, System Administrators, and Chief Security Officers.

eshurakAuthor Commented:
JunkMan - OfficeList already exists on the page.  No new objects are being created programatically.

Ragi - the lb.ID is the name of the Label that is being clicked.  I don't want to find my labels.  I want to use the command arguement of the Label to find the corresiponding listbox and clear it's selected value.  There are several label and listbox pairs on the aspx page.
0
Anurag ThakurTechnical ManagerCommented:
If you look up for the definition of FindControl in MSDN, it tells that you need to pass the ID of the control. Passing anything else will not return you the control.
So as i previously stated you cannot find your control using the command name you have to use the ID
0
eshurakAuthor Commented:
Ragi- Right, ID is string which is what is contained in the CommandArgument.

Below is the example from MSDN (http://msdn.microsoft.com/en-us/library/486wc64h.aspx) using a string:

Control myControl1 = FindControl("TextBox2");

0
eshurakAuthor Commented:
Found the solution:

            LinkButton lb = sender as LinkButton;
            ListBox List = (ListBox)Master.FindControl("ContentPlaceHolder1").FindControl(lb.CommandArgument);
            List.SelectedIndex = -1;

I had to be very specific on where to look.  Now List is no longer null.  
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
.NET Programming

From novice to tech pro — start learning today.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.