Checkbox server/client events

Question

I have a checkbox in repeater control. on changing it's bit value, it should prompt the alert message like do u wish to delete? and if yes is selected, the onselectedchange server event should be fired.

Right now. on clicking the checkbox i am using onclick event to fire the prompt but it is not able to fire the server event.

here is my code

<script language="javascript" type="text/javascript">

function CheckedChange() {
         if (confirm('Are you sure you want to delete?'))
             return true;
         else
             return false;
     }
</script>

<asp:Repeater ID="repQuestion" runat="server"  onitemcommand="repQuestion_ItemCommand"                                                    onitemdatabound="repQuestion_ItemDataBound">

<ItemTemplate>
<table  width="100%" cellspacing="0" cellpadding="0">
<tr>
<td>
<asp:CheckBox onclick="return CheckedChange();" ID="delete" runat="server" Checked='<%#DataBinder.Eval(Container.DataItem, "IsDeleted")%>' OnCheckedChanged="chkdelete_Click" />
</td>
</tr>
</table>
</ItemTemplate>
</asp:Repeater>

naveen · Accepted Answer · 2011-08-30T05:33:29.253

Work around this snippet.

The Repeater.

<asp:Repeater ID="Repeater1" runat="server">
    <ItemTemplate>
        <table>
            <tr>
                <td><%# Eval("Index") %></td>
                <td>
                    <asp:CheckBox ID="delete" runat="server" 
                            AutoPostBack="true"
                            Checked='<%# Convert.ToBoolean(Eval("IsDeleted")) %>'
                            Enabled='<%# !Convert.ToBoolean(Eval("IsDeleted")) %>'
                            OnCheckedChanged="chkdelete_Click" 
                            onclick="javascript:return CheckedChange(this)"/>              
                </td>
            </tr>
        </table>
    </ItemTemplate>
</asp:Repeater>

JavaScript

function CheckedChange(objCheckBox) {
    if (confirm('Are you sure you want to delete?')) {
        __doPostBack("'" + objCheckBox.id + "'", '');
        return true;
    }
    else {
        objCheckBox.checked = false;
        return false;
    }
}

Page_Load Event

protected void Page_Load(object sender, EventArgs e)
{
    try
    {
        if (!IsPostBack)
        {
            //bind gridview here
            DataTable dataTable = new DataTable
            {
                Columns = { "Index", { "IsDeleted", typeof(bool) } }
            };
            bool temp = true;
            for (var i = 0; i < 6; i++)
            {
                dataTable.Rows.Add((i + 1).ToString(), temp);
                temp = !temp;
            }

            Repeater1.DataSource = dataTable;
            Repeater1.DataBind();
        }
    }
    catch (Exception exception)
    {
        //Elmah.ErrorSignal.FromCurrentContext().Raise(exception);
    }
}

Well, I don't personally like exposing the __doPostBack but this seems to be the only way in this case.

On an unrelated side note, if you are showing deleted items, its better to show them disabled.

It is giving javascript error "Microsoft JScript runtime error: Object expected" on executing of html code. — Pankaj, Aug 30 '11 at 05:12
i have pasted my working snippet. what are you doing differently? perhaps not setting `AutoPostBack=true`? — naveen, Aug 30 '11 at 05:34
My last question in this thread - Why it is not recommended to exposing __doPostBack ?? — Pankaj, Aug 30 '11 at 08:46
@Pankaj: because thats framework version related. say at a future iteration say asp.net 10.0, the architects tend to postback using `__doit` then our code will be obslete. `__dopostback` is a name they give and its not guaranteed to stay for ever. — naveen, Aug 30 '11 at 10:08

score 1 · Answer 2 · answered Aug 30 '11 at 06:06

Try by passing the UniqueID (that is the name of the Checkbox).

<asp:Repeater ID="Repeater1" runat="server">
    <ItemTemplate>
        <table>
            <tr>
                <td><%# Eval("Index") %></td>
                <td>
                    <asp:CheckBox ID="delete" runat="server" 
                            AutoPostBack="true"
                            Checked='<%# Convert.ToBoolean(Eval("IsDeleted")) %>'
                            Enabled='<%# !Convert.ToBoolean(Eval("IsDeleted")) %>'
                            OnCheckedChanged="chkdelete_Click" 
                            onclick="javascript:return CheckedChange(this)"/>              
                </td>
            </tr>
        </table>
    </ItemTemplate>
</asp:Repeater>

JavaScript

function CheckedChange(objCheckBox) {
    if (confirm('Are you sure you want to delete?')) {
        __doPostBack("'" + objCheckBox.name + "'", '');
        return true;
    }
    else {
        objCheckBox.checked = false;
        return false;
    }
}

score 0 · Answer 3 · answered Jan 18 '17 at 19:23

Try this

    function confirmUser(checkBox)
    {
        if(checkBox.childNodes[0].checked === false){
            alert('Your alert message');
            }
    }

<asp:Repeater ID="rptSelecteduserRoles" runat="server" OnItemDataBound="rptSelecteduserRoles_OnItemDataBound">
<ItemTemplate>
                                                        
<asp:CheckBox ID="chkBox" CssClass="fieldLabel" AutoPostBack="False" onchange="confirmUser(this)"runat="server" Text='<%# Eval("Name") %>' />
                                                        
 </ItemTemplate>
 </asp:Repeater>

Checkbox server/client events

3 Answers3

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