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Checkboxlist  Select All checkbox

Posted on 2009-07-02
Last Modified: 2012-05-07
I have a checkboxlist and want a select all checkbox. The way I want it to work is that if they hit select all it checks all the boxes. The problem I am running into is that if they have 'item1' checked and you click "select all". I cant tell that select all is checked because in the selectedindexchanged event it is still showing me a value of item1.

How can I get this to work right? I basically want Select all to check all the boxes and if they have select all checked and uncheck any checkbox it unchecks select all.
    <form id="form1" runat="server">
        <asp:ScriptManager ID="ScriptManager1" runat="server">
        <asp:UpdatePanel ID="UpdatePanel1" runat="server">
        <asp:CheckBoxList ID="CheckBoxList1" runat="server" RepeatColumns="2" AutoPostBack="true">
            <asp:ListItem>Select All</asp:ListItem>

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Question by:bertino12
  • 2
  • 2

Expert Comment

ID: 24765246
Use a for loop... checking for all controls that are checkboxes. If you have some you don't want checked, then use a groupbox as a container for the checkboxes... now you will use two nested for loops.
Dim ctl As Object
        For Each ctl In Lookup.Controls
            if ctl is checkbox then
            'yourCheckbox.checked = true

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LVL 41

Accepted Solution

guru_sami earned 500 total points
ID: 24765271
Try this:
Protected Sub CheckBoxList1_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)
    If CheckBoxList1.Items(5).Selected = True Then
        For Each item As ListItem In CheckBoxList1.Items
            item.Selected = True
    End If
End Sub

This code has its own limitations .eg. Items(5) ..here this index 5 may change depending on the number of checkboxes. But it should give you an idea where to head.

Author Comment

ID: 24766208
Could it be done through javascript?

Can I wire a javascript function to the  checkboxlist items so that when they are clicked it fires a javascript function that if false unchecks the "All" option and if true checks all the checkboxes?

How could I do this?
LVL 41

Expert Comment

ID: 24766411
May be you can try Adding onchange attribute to CBL OnPageLoad. Not sure how would that go...but because using a single checkbox to Select ALL and Deselect ALL would create a problem.
Say someone wants to select just one checkbox...at that time SelectAll will not be selected ..that will make delect all implied if using a singel Checkbox.

Check using two buttons like this: http://www.dotnetcurry.com/ShowArticle.aspx?ID=77

Author Comment

ID: 24766996
I ended up doing it in javascript:

    Private Sub addAttributes()
        Me.cbLaws.Items(11).Attributes.Add("style", "color: red")
        For i As Integer = 0 To 11
            If i = 11 Then
                Me.cbLaws.Items(i).Attributes.Add("onclick", "javascript:Select(true)")
                Me.cbLaws.Items(i).Attributes.Add("onclick", "javascript:Select(false)")
            End If
    End Sub
<script language="javascript"  type="text/javascript"> 
function Select(flag){
    if(flag==true) {  
        if(document.getElementById("ctl00_PageBody_cbLaws_11").checked == true) {
            var i=0;
            for (i=0;i<=11;i++)
                document.getElementById("ctl00_PageBody_cbLaws_" + i).checked = true;
        if(document.getElementById("ctl00_PageBody_cbLaws_11").checked == false) {
            var i=0;
            for (i=0;i<=11;i++)
                document.getElementById("ctl00_PageBody_cbLaws_" + i).checked = false;
        document.getElementById("ctl00_PageBody_cbLaws_11").checked = false;

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