Remove Items from ListBox

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Hi Friends,
I am adding items to List-box using java-script;
Now , on Button click server side event, when I try to remove selected items, I get item count 0;

I want to remove items from server side click event only.

This is what I have on Keyup event of text box.

<asp:TextBox ID="txtPONo" runat="server"  onKeyUp="inputKeyUp(event)"></asp:TextBox>
<asp:Button ID="btnAddToList" runat="server" OnClick="btnRemoveFromList_Click" Text="Remove PO" />

<script type="text/javascript">
    function inputKeyUp(e) {
        e.which = e.which || e.keyCode;
        if (e.which == 13) {
            var varFromBox = document.all('lstPONo');
            var ListBox = document.getElementById('ctl00_MainContentPlaceHolder_lstPONo');
            var TextBox = document.getElementById('ctl00_MainContentPlaceHolder_txtPONo');

            var myOption = new Option();
            myOption.text = document.getElementById('ctl00_MainContentPlaceHolder_txtPONo').value; //Textbox's value
            myOption.value = document.getElementById('ctl00_MainContentPlaceHolder_txtPONo').value; //Textbox's value
            ListBox.add(myOption);
            document.getElementById('ctl00_MainContentPlaceHolder_txtPONo').value = '';
        }
    }
</script>

And my button click event on server side :

protected void btnRemoveFromList_Click(object sender, EventArgs e)
        {
            try
            {
                while (lstPONo.Items.Count > 0)
                {
                    lstPONo.Items.Remove(lstPONo.SelectedItem);
                }
            }
            catch (Exception ex)
            {
                XITingExceptionProcessor.ProcessException(this, ex);
            }
        }

I cant find out, where I am going wrong.
Please help,

Thanks,
Lok..

Posted 20-Mar-12 23:18pm

Lokesh Zende

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Comments

ZurdoDev 21-Mar-12 7:57am

Silly question, but if you are adding them client side why don't you also remove them client side?

solutions@ashish 21-Mar-12 9:07am

Agree with ryanb31,

If You create any thing using javascript so why you want to remove them using server side

3 solutions

Solution 2

Hi,
You can remove selected Items from list at server side on click of button.
Listbox remove selected items.
Find list of selected list items and remove them from list box.

Posted 21-Mar-12 7:06am

satalaj

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S@53K^S · Accepted Answer · 2012-03-21T05:31:00

Solution 1

You are adding items on the HTML generated on the client browser so server has no idea of what is being done in the client browser.So you always get the count of items 0.

Posted 21-Mar-12 5:31am

S@53K^S

Comments

Lokesh Zende 22-Mar-12 0:33am

Thanks for this info, Sastry_kunapuli...

shreekar · Accepted Answer · 2012-03-21T09:40:00

As pointed out by Sastry_kunapuli, you are adding the items on client side, the server has no idea about them, so you are getting count = 0 at server side.

If you must do it this way, then here is a way:

1. Add a hidden input field in the form.

HTML

<input type="hidden" name="added_to_list" id="added_to_list" value=""></input>

2. Before submitting the form to the server, populate the hidden input field with the items added to the list box at client side. Use some delimiter between entries.

3. On the server, read the hidden input field to retrieve the added items, separating on the delimiter.