getting users from SharePoint Groups and Binding them to Simple HTML Table

try
            {
                string strAllUsers = string.Empty;
                SPSecurity.RunWithElevatedPrivileges(delegate()
                {
                    strAllUsers += "<Table width='100%' cellpadding='0' cellspacing='0'>";
                    strAllUsers += "<Tr>";
                    strAllUsers += "<Td colspan='3' bgcolor='#add8e6'>";
                    strAllUsers += "</Td>";
                    strAllUsers += "</Tr>";
                    strAllUsers += "<Tr>";
                    strAllUsers += "<Td colspan='3' Align='Center'>";
                    strAllUsers += "<Strong>";
                    strAllUsers += "Users Using this Site";
                    strAllUsers += "</Strong>";
                    strAllUsers += "</Td>";
                    strAllUsers += "</Tr>";
                    strAllUsers += "<Tr>";
                    strAllUsers += "<Td bgcolor='#add8e6'>";
                    strAllUsers += "<Strong>";
                    strAllUsers += "UserName";
                    strAllUsers += "</Strong>";
                    strAllUsers += "</Td>";
                    strAllUsers += "<Td bgcolor='#add8e6'>";
                    strAllUsers += "<Strong>";
                    strAllUsers += "SharePoint Group";
                    strAllUsers += "</Strong>";
                    strAllUsers += "</Td>";
                    strAllUsers += "<Td bgcolor='#add8e6'>";
                    strAllUsers += "<Strong>";
                    strAllUsers += "EmailID";
                    strAllUsers += "</Strong>";
                    strAllUsers += "</Td>";
                    strAllUsers += "</Tr>";
                    strAllUsers += "<Tr>";
                    strAllUsers += "<Td colspan='3' bgcolor='#add8e6'>";
                    strAllUsers += "</Td>";
                    strAllUsers += "</Tr>";
                    SPWeb currentWeb = SPContext.Current.Web;
                    foreach (SPGroup grp in currentWeb.Groups)
                    {
                        foreach (SPUser user in grp.Users)
                        {
                            string strUser = string.Empty;
                            string strGroup = string.Empty;
                            string strUserEmail = string.Empty;
                            strUser = user.Name;
                            strGroup = grp.Name;
                            strUserEmail = user.Email;
                            strAllUsers += "<Tr>";
                            strAllUsers += "<Td>";
                            strAllUsers += strUser;
                            strAllUsers += "</Td>";
                            strAllUsers += "<Td>";
                            strAllUsers += strGroup;
                            strAllUsers += "</Td>";
                            strAllUsers += "<Td>";
                            strAllUsers += strUserEmail;
                            strAllUsers += "</Td>";
                            strAllUsers += "</Tr>";
                            strAllUsers += "<Tr>";
                            strAllUsers += "<Td colspan='3' bgcolor='#add8e6'>";
                            strAllUsers += "</Td>";
                            strAllUsers += "</Tr>";
                        }
                    }
                    strAllUsers += "</Table>";
                    writer.Write(strAllUsers);
                });
            }
            catch (Exception ex)
            {
                writer.Write(ex.ToString());
            }