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How can I select all the items in a System.Windows.Forms.CheckedListBox

I need to select all the items in CheckedListBox on the check / uncheck of a checkbox click event.
The CheckedListBox is bound to a Generic List as its datasource

chkListBox.CheckOnClick = true;
chkListBox.DataSource = listData;
chkListBox.DisplayMember = "Description";
chkListBox.ValueMember = "Value";

I have also a SelectAll checkbox, when the users checks the SelectAll I want to have all the items in the chkListBox checked.
When the user unchecks the SelectAll checkbox I want all the items unchecked.
I am using .NEt 4.0

Kyle Abrahams, PMP

credit: http://www.dotnetcurry.com/showarticle.aspx?ID=77

<script language="javascript" type="text/javascript">
 
function CheckBoxListSelect(cbControl, state)
{    
       var chkBoxList = document.getElementById(cbControl);
        var chkBoxCount= chkBoxList.getElementsByTagName("input");
        for(var i=0;i<chkBoxCount.length;i++) 
        {
            chkBoxCount[i].checked = state;
        }
        
        return false; 
}
 
</script>


<asp:CheckBoxList ID="cbl1" runat="server"></asp:CheckBoxList><br />
 
Select <a id="A1" href="#" onclick="javascript: CheckBoxListSelect ('<%= cbl1.ClientID %>',true)">All</a>
| <a id="A2" href="#" onclick="javascript: CheckBoxListSelect ('<%= cbl1.ClientID %>',false)">None</a>    
 
    <br />
    <br />
 
    <asp:CheckBoxList ID="cbl2" runat="server">
    </asp:CheckBoxList>
    Select <a id="A3" href="#" onclick="javascript: CheckBoxListSelect ('<%= cbl2.ClientID %>',true)">All</a>
 
| <a id="A4" href="#" onclick="javascript: CheckBoxListSelect ('<%= cbl2.ClientID %>',false)">None</a>

Open in new window

It's a lot easier to use the links. If you do the checkbox inside the listbox than technically you should deselect the "checkall" box if they uncheck any other box.

You would also need to add logic to check the checkall box if they checked each of the items.

EG:
If checkbox for check all is checked
check all items
if checkbox for check all is unchecked
uncheck all items
if another checkbox is unchecked
uncheck checkall (don't uncheck the rest)
if all but select all is checked
check check all.

VS having the links.

ASKER CERTIFIED SOLUTION

Carl Tawn

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