Getting users from SharePoint groups and binding it to a Simple Asp.Net Table Object

using System;
using System.Runtime.InteropServices;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Serialization;
using System.Security;
using Microsoft.SharePoint;
using Microsoft.SharePoint.WebControls;
using Microsoft.SharePoint.WebPartPages;
using System.Drawing.Design;
[assembly:AllowPartiallyTrustedCallers]
namespace AllUsersWebPart
{
    [Guid("31e57d3c-47e9-432e-99ce-ad06626d93e2")]
    public class AllUsersWebPart : System.Web.UI.WebControls.WebParts.WebPart
    {
        Label lblName;
        Label lblgroups;
        Table tblAllUsers;
        string strError = string.Empty;
        public AllUsersWebPart()
        {
        }

        protected override void CreateChildControls()
        {
            try
            {
                tblAllUsers = new Table();
                //tblAllUsers.Width = 100;
                //tblAllUsers.Height=100;
               // tblAllUsers.CellPadding=0;
                //tblAllUsers.CellSpacing=0;
                lblgroups = new Label();
                lblName = new Label();

                CreateHeaderRow(); // Will Add a header Row to the Table.

                using (SPSite SPSite = new SPSite(SPContext.Current.Site.ID))
                {
                    using (SPWeb SPWeb = SPSite.OpenWeb(SPContext.Current.Web.ID))
                    {

                        SPUserCollection AllSPWebUsers = SPContext.Current.Web.AllUsers;

                        SPGroupCollection AllSPWebGroups = SPContext.Current.Web.Groups;

                        //Iterate through each group in the current site.

                        foreach (SPGroup grp in AllSPWebGroups)
                        {
                            SPUserCollection UsersInGroup = grp.Users;

                            foreach (SPUser user in UsersInGroup)
                            {
                                lblName.Text = user.Name;

                                foreach (SPGroup usergrp in user.Groups)
                                {
                                    lblgroups.Text = usergrp.Name;
                                }

                                AddToTable(lblName.Text, lblgroups.Text);
                            }
                        }
                    }
                }

                this.Controls.Add(tblAllUsers);
            }
            catch (Exception ex)
            {
                strError += ex.ToString();
            }
        }
        protected void AddToTable(string UserName, string grp)
        {
            TableRow r = new TableRow();

            TableCell CellName = new TableCell();
            CellName.Text = UserName;
            r.Cells.Add(CellName);

            TableCell CellPermissions = new TableCell();
            CellPermissions.Text = grp;
            r.Cells.Add(CellPermissions);

            tblAllUsers.Rows.Add(r);
        }
        protected void CreateHeaderRow()
        {

            TableHeaderRow headerRow = new TableHeaderRow();
            headerRow.BackColor = System.Drawing.Color.LightBlue;

            TableHeaderCell headerTableCell1 = new TableHeaderCell();
            TableHeaderCell headerTableCell2 = new TableHeaderCell();
            headerTableCell1.Text = "User Name";
            headerTableCell1.Scope = TableHeaderScope.Column;

            headerTableCell2.Text = "Group";
            headerTableCell2.Scope = TableHeaderScope.Column;

            headerRow.Cells.Add(headerTableCell1);
            headerRow.Cells.Add(headerTableCell2);

            tblAllUsers.Rows.AddAt(0, headerRow);
        }
    }
}