ASP.NET

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.IO;
using System.Xml;
using System.Xml.XPath;
using AccessRequestForm.UtilityServices;
using AccessRequestForm.BusinessServices;
using AccessRequestForm.Models;
using AjaxControlToolkit;

namespace AccessRequestForm
{
    public partial class AssignRole : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!Page.IsPostBack)
            {
                IQueryable<MasterRole> roleList = Role.SelectAll(Convert.ToInt32(strBUSelected));
                lstRoles.Items.Clear();
                foreach (MasterRole role in roleList)
                {
                    ListItem li = new ListItem(role.role_business_desc.ToString(), role.role_id.ToString());
                    lstRoles.Items.Add(li);
                }

                UpdateRoleGrid(roleList);

            }
        }

        public void UpdateRoleGrid(IQueryable<MasterRole> roleList)
        {
            //Databind the Grid
            grdRoles.DataSource = roleList;
            grdRoles.DataBind();
        }

        [System.Web.Services.WebMethod]
        [System.Web.Script.Services.ScriptMethod]
        public static string[] GetCompletionList(string prefixText, int count, string contextKey)
        {
            IQueryable<MasterRole> roleList = Role.SelectStartPattern(Convert.ToInt32(contextKey), prefixText);
            List<string> items = new List<string>(count);
            int i = 0;
            foreach (MasterRole role in roleList)
            {
                if (i++ < count)
                {
                    string strName = role.role_business_desc.ToString();
                    items.Add(strName);
                }
            }
            
            //I get the error here "An object reference is required for the non-static field, method, or property 'AccessRequestForm.AssignRole.UpdateRoleGrid"
            UpdateRoleGrid(roleList);

            return items.ToArray();
        }
    }
}