Cannot access html listbox control from code behind.

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Hello guys,
I have a html listbox which i have populated by xml parsing. But when i am trying to get the selected items of this html listbox, i am unable to get any itmes in it, i always get its count as null.
I tried this

C#

Control drpSkills_ctrl = (ListBox)FindControl("ctl00$ContentPlaceHolder1$drpSkills");

With the above code i am able to get the listbox in rpSkills_ctrl but i dont get .items.count property.

Can anyone help how can i get the listbox and do foreach or for loop on its items

Posted 22-Sep-11 1:46am

prot0col

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Suresh Suthar 22-Sep-11 7:48am

Is it server control? Means runat="server".

2 solutions

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jim lahey · Answer 1 · 2011-09-22T01:56:00

Solution 1

Can't you access the control directly? Even if it's a server side Html control like this:

ASP.NET

<select runat="server" id="drpSkills">
//options
</select>

You should still be able to access it directly like this:

C#

Control drpSkills_ctrl = drpSkills;

or if the problem is that you've found the control, but you can't access it's items collection, you'll need to cast it to the correct type which should be HtmlSelect:

http://msdn.microsoft.com/en-us/library/807bc327.aspx[^]

Posted 22-Sep-11 1:56am

jim lahey

Comments

[no name] 22-Sep-11 8:43am

Thanks for the reply sir, i did this

HtmlSelect hs = new HtmlSelect();
hs.DataSource = drpSkills.Items;
hs.databind();

but still am getting items count = 0

jim lahey 22-Sep-11 8:49am

Well of course that's not going to work. Try this:

HtmlSelect drpSkills_ctrl = (HtmlSelect)FindControl("ctl00$ContentPlaceHolder1$drpSkills");

[no name] 22-Sep-11 9:11am

Thanks but still not working for me :(
i did

HtmlSelect drpSkills_ctrl = (HtmlSelect)FindControl("ctl00$ContentPlaceHolder1$drpSkills");
for (int j = 0; j <= drpSkills_ctrl.Items.Count; ++j)
{
if (drpSkills_ctrl.Items[j].Selected)
{
arr.Add(drpSkills_ctrl.Items[j].Value);
}
}

I gets count as 0 only.

jim lahey 22-Sep-11 9:16am

post the code where you populate the HtmlSelect

[no name] 23-Sep-11 1:09am

My code is something like this, first i fetch data from xml, put it in array and then call another function to remove duplicate values and then append all the unique values in my dropdown.
<pre lang="c#">
<script type="text/javascript" language="javascript">
$(document).ready(function()
{
$.get('/files/Test.xml', function(d){
});
$.ajax({
type: "GET",
url: "/files/Test.xml",
dataType: "xml",
success: parseXml
});
</script>
<script type="text/javascript" language="javascript">

function parseXml(xml)
{
document.getElementById('ctl00_ContentPlaceHolder1_rdoSubskill').checked = true;

var arrSpecialization = new Array();
var arrSkills = new Array();
var arrSubSkills = new Array();
//For getting all specialization in an array
$(xml).find("special").each(function()
{
var test = $(this).attr("spnm") + ' , '+ $(this).attr("spid");
arrSpecialization.push(test);
});
FilterSpecialization(arrSpecialization);
}

function FilterSpecialization(arr)
{
var i;
var len = inputArray.length;
var outputArray = [];
var temp = {};
for (i = 0; i < len; i++)
{
temp[inputArray[i]] = 0;
}

for (i in temp)
{
outputArray.push(i);
}
$('#ctl00_ContentPlaceHolder1_drpSpecialization >option').remove();
$('#ctl00_ContentPlaceHolder1_drpSpecialization').append($('<option></option>').val('0').html('--All Specialization--'));
$.each(outputArray, function(val, text) {
$('#ctl00_ContentPlaceHolder1_drpSpecialization').append( $('<option></option>').val(text.split(",")[1]).html(text.split(",")[0]))
});
}
</script>
</pre>

Here is my HTML select code
<pre lang="HTML">
<select id="drpSkills" önclick="FilterSubSkills(this)" size="12" multiple="true" runat="server" style="width: 220px">
</pre>

This function FilterSubSkills() is used to get all the selected values from my listbox and on the basis of these values i again populate another listbox with the respective values.

Now in my code behind i am getting drpskills but its item count is 0.

Wonde Tadesse · Answer 2 · 2011-09-22T12:59:00

Solution 3

In addition to jim answer, use ClientID property of the control. i.e

C#

HtmlSelect drpSkills_ctrl = (HtmlSelect)FindControl(drpSkills.ClientID)

In addition to this ,the way the data is bound to ListBox or HtmlSelect is very important. i.e Are you binding to the data to a Page Load by checking a PostBack. If you didn't check a PostBack, then you won't be able to get Selected item from the list. Here is a good MSDN example. HtmlSelect Server Control Declarative Syntax[^]

Posted 22-Sep-11 12:59pm

Wonde Tadesse

Comments

[no name] 23-Sep-11 1:27am

dint worked for me, i have seen that link before, its showing how to populate from listboxes which have its options hardcoded, my listbox is populated dynamically.

Wonde Tadesse 23-Sep-11 9:52am

Can you post the full code that binds the listbox?