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Listbox in a div container.....how to make it work?!?!?1

ciara_barry123
on
Medium Priority
441 Views
Last Modified: 2008-02-01
I have a listbox on my asp.net website.  I wanted to display horizontal scrollbars on the listbox...so I put the listbox in a div container.  Now the scrollbars both display, however I cannot seem to capture the selected item in the listbox now.  It selects fine but the selectedindex is always -1!!!!!!
any help is much appreciated:
here is the code for the listbox:

           <div id="myContainer" style="height:70px;width:223px;overflow:scroll; z-index: 116; left: 145px; position: absolute; top: 361px;" atomicselection="false" >
 <asp:ListBox ID="ChangeType" runat="server" DataSourceID="ChangeDataSource"
            DataTextField="NAME"
            DataValueField="NAME" SelectionMode="Multiple"></asp:ListBox>
  </div

it took me ages to get the scrollbar part to work and now this problem :-)

HELP :-)
Comment
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hi,

i have reproduced the code ur using

if(!IsPostBack)
{
  connect();//ur databing code
}

put ur list box connecting code with the if(!IsPostBack)

it works

b u d d h a

Author

Commented:
jeebukarthikeyan  - thanks for the comment :-)

excuse my ignorance...i'm a little confused as to where exactly I would put the code?

If(!IsPostBack)
{
  connect();//ur databing code
}

I'm using VB code....
hi,

i have created some thing like ur
<form id="Form1" method="post" runat="server">
      <div id="myContainer" style="Z-INDEX:116;LEFT:167px;OVERFLOW:scroll;WIDTH:223px;POSITION:absolute;TOP:100px;HEIGHT:70px">
            <asp:ListBox ID="lst" runat="server" SelectionMode="Multiple" AutoPostBack="True"></asp:ListBox>
      </div>
      <asp:ListBox ID="Listbox1" runat="server" SelectionMode="Multiple" AutoPostBack="True"></asp:ListBox>
</form>

this is the function which will populate listbox

void connect()
{
  DataTable dt      =      new DataTable();
  DataColumn dc      =      new DataColumn("name");

  dt.Columns.Add(dc);

  DataRow dr      ;
  dr      =      dt.NewRow();
  dr["name"]="aaa";
  dt.Rows.Add(dr);

  dr      =      dt.NewRow();
  dr["name"]="bbb";
  dt.Rows.Add(dr);

  dr      =      dt.NewRow();
  dr["name"]="bbb";
  dt.Rows.Add(dr);

  lst.DataTextField      =      "name";
  lst.DataValueField      =      "name";

  lst.DataSource      =      dt;
  lst.DataBind();

 }

//code for selected index change
private void lst_SelectedIndexChanged(object sender, System.EventArgs e)
{
      Response.Write( lst.SelectedIndex.ToString());
}

//form load
if(!IsPostBack)
{

      connect();
}

b u d d h a

Author

Commented:

jeebukarthikeyan  - thanks again for the comments....
I think I was confused because I'm using vb not c#?
I'll post all of my code to see if it helps:

in the source section:
          <div id="myContainer" style="height:70px;width:223px;overflow:scroll; z-index: 116; left: 145px; position: absolute; top: 361px;" atomicselection="false" >
 <asp:ListBox ID="ChangeType" runat="server" DataSourceID="ChangeDataSource"
            DataTextField="NAME"
            DataValueField="NAME" SelectionMode="Multiple" AutoPostBack="True"></asp:ListBox>
  </div> &nbsp; &nbsp;
         
on the page_load event in the vb code (I'm connecting to a datasource):
        Me.ChangeType.DataBind()
        ChangeType.Rows = ChangeType.Items.Count

Author

Commented:
and just to clarify:
when the listbox is not in the div tag, it works perfectly.
when I put it in the div tag:
when you select anything in the listbox, the selected index is always -1, so it doesn't seem to be registering that something is selected, even though when you look on the screen, you can see it's selected.

I've been stuck on this all day.....
hi,
where ur calling the function for populating the listboxes....

can u put the code here

b u d d h a

Author

Commented:
Hi ,
Thanks again for spending time on this:
I'm not actually calling any function to populate..it's automatically bound to the datasource so populates automatically on load....
hope this makes sense

hi,

that is where the problm i think

populate the datalist form the function

it will work

u can use my connect() function
for that

b u d d h a

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Author

Commented:
no it still doesn't work I'm afraid :-(

any other suggestions?
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Most Valuable Expert 2012
Top Expert 2008

Commented:
What happens if you use overflow:auto?

Bob

Author

Commented:
thanks Bob...but unfortunately it still doesn't work it  I use overflow auto :-(
CERTIFIED EXPERT
Most Valuable Expert 2012
Top Expert 2008

Commented:
Ok, because I see overflow:scroll.  Are the values for the DropDownList unique?  Did it work before you put it in the <div>?

Bob

Author

Commented:
Hi bob,

just leaving now for the day but said i'd quickly repsond

yes it worked perfectly before I put it in the div
i only put in the div so I could have a horizontal scrollbar...and when i got that working, I could no longer select :-)
typical

if you have any other ideas, let me know and I'll try them when I get into work tomorrow

thanks for the help

Author

Commented:
ps: sorry bob, I meant that I changed it to overflow auto and it still didn't work :-)
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Most Valuable Expert 2012
Top Expert 2008
Commented:
I did a small test:

<div style="LEFT:20px;OVERFLOW:auto;WIDTH:200px;POSITION:absolute;TOP:20px;HEIGHT:300px">
   <asp:ListBox id="ListBox1" runat="server" Width="500px" AutoPostBack="True">
      <asp:ListItem Value="This is a test of the radio broadcast system">This is a test of the radio broadcast system</asp:ListItem>
    <asp:ListItem Value="This is another long text string">This is another long text string</asp:ListItem>
    </asp:ListBox>
</div>

The SelectedIndex changed as expected.

Bob

Author

Commented:
Ok I figured it out..all it needed was  a fresh brain:
in the load section I had the following code:
            Me.ChangeType.DataBind()
            ChangeType.Rows = ChangeType.Items.Count
which meant every time the user clicked on the listbox, the form was loaded and thus the listbox was reloaded...losing the selection
i added the following code to ensure it was only databound on the first load and it works perfectly....

  If FirstTimeLoad <> False Then
                    Me.ChangeType.DataBind()
            ChangeType.Rows = ChangeType.Items.Count
            FirstTimeLoad = False
        End If
thanks for all the help I'm going to split the points:
hope you think that's fair......


 
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