Recently I encounter question at the forums.asp.net asking if how to move selected ListItems from one  CheckBoxList to another. So I decided to post the solution that I have provided in that thread so that others can refer this post if they will encounter the same thing.

Here’s the code block below:

ASPX:

<table>
    <tr>
        <td> 
            <asp:CheckBoxList ID="CheckBoxList1" runat="server">
                <asp:ListItem>Player1</asp:ListItem>
                <asp:ListItem>Player2</asp:ListItem>
                <asp:ListItem>Player3</asp:ListItem>
                <asp:ListItem>Player4</asp:ListItem>
                <asp:ListItem>Player5</asp:ListItem>
                <asp:ListItem>Player6</asp:ListItem>
            </asp:CheckBoxList>
        </td>
        <td>
            <asp:Button ID="ButtonAdd" runat="server" Text=">>" 
                        onclick="ButtonAdd_Click" />
            <br />
            <asp:Button ID="ButtonRemove" runat="server" 
                        Text="<<" onclick="ButtonRemove_Click" />
        </td>
        <td>
            <asp:CheckBoxList ID="CheckBoxList2" runat="server">
            </asp:CheckBoxList>
        </td>
    </tr>
</table>

RELEVANT CODES:

protected void ButtonAdd_Click(object sender, EventArgs e){

        for (int i = CheckBoxList1.Items.Count - 1; i >= 0; i--)
        {
            if (CheckBoxList1.Items[i].Selected)
            {
                CheckBoxList2.Items.Add(CheckBoxList1.Items[i]);
                CheckBoxList2.ClearSelection();
                CheckBoxList1.Items.Remove(CheckBoxList1.Items[i]);
            }
        }
}

protected void ButtonRemove_Click(object sender, EventArgs e){

        for (int i = CheckBoxList2.Items.Count - 1; i >= 0; i--)
        {
            if (CheckBoxList2.Items[i].Selected)
            {
                CheckBoxList1.Items.Add(CheckBoxList2.Items[i]);
                CheckBoxList1.ClearSelection();
                CheckBoxList2.Items.Remove(CheckBoxList2.Items[i]);
            }
        }
}

That's it! I hope someone find this post useful!