How to call a code-behind method from aspx or asp page?

The code in .aspx page

<asp:Panel ID="PanelId" runat="server" Width="100%" Visible="true">

    <div class="classname " style="font-size: 80%; font-family: arial, helvetica, verdana">

        <br />

        <br />

        <table align="left" border="0" cellspacing="0" cellpadding="0" width="100%" class="classname ">

            <tr align="left" valign="middle">

                <td>

                    &nbsp;

                </td>

                <td>

                    <b>List of documents:</b>

                </td>

            </tr>

            <tr align="left" valign="middle">

                <td>

                    &nbsp;

                </td>

                <td>

                    <ul>

                        <%= this.CsharpMethod()%>

                    </ul>

                </td>

            </tr>

        </table>

    </div>

</asp:Panel>

The c sharp code in  .aspx.cs file

        protected string CsharpMethod ()

        {

string dDoco = string.Empty;

                // Retrieve data from database

                ArrayList al = datalistMethodName();

                if (al.Count > 0)

                {

                    dDoco += "<br><table align=\"left\" border=\"2\" cellpadding=\"2\" width=\"95%\" >";

                    dDoco += "<tr align=\"left\" valign=\"middle\">";

                    dDoco += "<td><b>Document</b></td><td><b>Document Type</b></td></tr>";

                    foreach (var item in al)

                    {

                        dDoco += "<tr align=\"left\" valign=\"middle\" ><td>" + item.Value.ToString() + "</td><td>" + item.Key.ToString() + "</td></tr>";

                    }

                    dDoco += "</table><br><br><br><br>";

                }

                return dDoco;

            }