Multi Select DropDown with CheckBox

Add the following Scripts

Add the Following Scripts

 <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>

    <link href="http://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.0.3/css/bootstrap.min.css"

        rel="stylesheet" type="text/css" />

    <script type="text/javascript" src="http://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.0.3/js/bootstrap.min.js"></script>

    <link href="http://cdn.rawgit.com/davidstutz/bootstrap-multiselect/master/dist/css/bootstrap-multiselect.css"

        rel="stylesheet" type="text/css" />

    <script src="http://cdn.rawgit.com/davidstutz/bootstrap-multiselect/master/dist/js/bootstrap-multiselect.js"

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

    <script type="text/javascript">

        $(function () {

            $('[id*=lsNames]').multiselect({

                includeSelectAllOption: true

            });

        });

    </script>

<asp:ListBox ID="lsNames" runat="server" SelectionMode="Multiple">

        <asp:ListItem Text="a" Value="1" />

        <asp:ListItem Text="b" Value="2" />

        <asp:ListItem Text="c" Value="3" />

        <asp:ListItem Text="d" Value="4" />

        <asp:ListItem Text="e" Value="5" />

    </asp:ListBox>

       <asp:Button ID="Button1" runat="server" Text="Button" OnClick="Button1_Click" />

on button click 

write the following code

string message = "";

        foreach (ListItem item in lsNames.Items)

        {

            if (item.Selected)

            {

                message += item.Text + " " + item.Value + "\\n";

            }

        }

        ClientScript.RegisterClientScriptBlock(this.GetType(), "alert", "alert('" + message + "');", true);

Output