listbox values on server side

Question

0.00/5 (No votes)

See more:

Hi All,
I desperately need help with the following:
i have a list box control that is populated with dates. This happens on client side(using javascript)
but now i need to save the listbox values to the DB which happens at server side on a button click event.
My prob is the listbox is empty when i try to do this.
Please help
Code is as follows:
Client side:
listbox

HTML

<asp:ListBox ID="lstDelDate" runat="server" ViewStateMode ="Enabled" AutoPostBack ="true" > 
<button type="button"  önclick="JavaScript:SelectDate()">Add DeliveryDate</button>

The function SelectDate adds the selected calender dates to the listbox
please Help
Thanks.

Posted 9-May-11 0:17am

AnnSJ

Updated 9-May-11 1:48am

Simon_Whale

v2

Add a Solution

Comments

Ankur^\m/ 9-May-11 6:20am

ViewStateMode = "Enabled"
I don't see such attribute available for me in VS.

Ankur^\m/ 9-May-11 6:31am

Does the ListBox gets populated properly with the required values?

AnnSJ 9-May-11 7:41am

Such a property exists.. yes the listbox does get the selectd dates

Ankur^\m/ 9-May-11 7:50am

You have called SelectDate() function on click of the button? Don't you want it pre-loaded i.e when the page loads? I guess you would want to move it to body onload.

Ankur^\m/ 9-May-11 7:52am

Try this,
Add return true; after the listbox gets populated in the JavaScript function.
And call the method OnClientClick of the Button like this - OnClientClick="return populateListBox();"

Let me know if that helps.

AnnSJ 9-May-11 8:08am

Sorry Ankur.
i tried return true after the listlox is populated but it gives me an error. I dont get the onCLientClick function in the intellisense. This is my code for inserting into the listbox at cleint side:
function SelectDate() {

//alert('<%=dt %>');
alert(document.getElementById('<%= txtDeliveryDate.ClientID %>').value);

var lst = document.getElementById('<%= lstDelDate.ClientID %>');

if (lst.options.length > 0) {
for (var i = 0; i < lst.options.length; i++) {
var txt = lst.options[i].text;
alert(txt)
if (txt == document.getElementById('<%= txtDeliveryDate.ClientID %>').value) {
alert("That option is already included in the list - please enter another date");
return false;
}
}
}
lst.options[lst.length] = new Option(document.getElementById('<%= txtDeliveryDate.ClientID %>').value, document.getElementById('<%= txtDeliveryDate.ClientID %>').value);
return True;
}

Ankur^\m/ 9-May-11 8:17am

Two things:
return True; 't' will be small. JavaScript is case sensitive.
Why do you have AutoPostBack of the ListBox set to true? Remove this part - AutoPostBack ="true". I think this is resetting the fields.

AnnSJ 9-May-11 8:52am

thnks ankur.. did that...
now my code looks like this:
<button type="button" önclick = "JavaScript:SelectDate()" >Add DeliveryDate</button>listbo is getting populated.. but still count is 0 at server side

Ankur^\m/ 9-May-11 8:55am

I don't know what's the problem. Just do one more thing - change onclick to OnClientClick.
Let me know.

AnnSJ 11-May-11 6:48am

gives me an error when i change onclick to onClientClick. my button is a html button not asp button. i have been trying to use Request.Form("lstDelDate"), but even taht return a null object!

Ankur^\m/ 11-May-11 6:58am

Request.Form("lstDelDate") returns a null? How is that possible? I mean if the listbox has some value, it must NOT be null.
This just proves one thing - your listbox doesn't have anything when the page is posted. You need to confirm that by putting debugger at the JavaScript code which is executed before the page gets posted.

Simon_Whale 9-May-11 9:31am

Right to be honest I'd have to research your question a bit more.. It appears that as your adding code to the page on the client side, the server side code doesn't know about it! hence your .net code doesn't see any changes to the listbox. I would suggest that you have a read of this article to see if it helps you!

http://www.vijaykodali.com/Blog/post/2007/12/14/Add-Delete-Items-in-DropDownList2c-ListBox-using-Javascript.aspx

If this doesn't help then Im unsure of how to solve it for you without looking at other solutions such as jquery / json webservice etc.

Sorry can't be of more help
Simon

AnnSJ 10-May-11 2:59am

thnx will keep working on it. will let u knwo if i find a soln. thnx for teh help in any case :)

Simon_Whale 9-May-11 6:37am

how are you saving / attempting to save them back to the database?

AnnSJ 9-May-11 7:42am

using a button click event handler. i want to loop through the list box and enter rows for into tehtabvel with each of teh dates

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Simon_Whale · Answer 1 · 2011-05-09T01:49:00

Solution 1

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    For i As Integer = 0 To ListBox1.Items.Count - 1
        'Here you would do the code that would pass it to the database to be saved
    Next
End Sub

This should give you the general idea of what you need to do if you need more help then just shout.

Posted 9-May-11 1:49am

Simon_Whale

Comments

AnnSJ 9-May-11 7:59am

Hi Simon.. yes i have already doen that but my prob is Listbox1.items.count is 0 even after being populated

Simon_Whale 9-May-11 8:09am

your code snippet shows the list box to be lstDelDate does that control have a count?

AnnSJ 9-May-11 8:46am

my prob exactly.the count is 0 even after i populate it with values