Loading huge data in a Silverlight AutoCompleteBox

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using System.ComponentModel;
using System.Collections;

namespace FastLoadingACB
{
    public partial class FastLoadingACB : UserControl//,INotifyPropertyChanged
    {
        #region Members
        private int counter = 0;
        public event SelectionChangedEventHandler FastLoadingACBSelectionChanged;
        #endregion

        #region Ctor
        public FastLoadingACB()
        {
            InitializeComponent();
        }
        #endregion

        #region Dependency Properties
        public double FastLoadingACBWidth
        {
            get { return (double)this.GetValue(FastLoadingACBWidthProperty); }
            set { this.SetValue(FastLoadingACBWidthProperty, value); }
        }
        public IEnumerable FastLoadingACBItemsSource
        {
            get { return (IEnumerable)this.GetValue(FastLoadingACBItemsSourceProperty); }
            set { this.SetValue(FastLoadingACBItemsSourceProperty, value); }
        }
        public int MaxItemsInDropDown
        {
            get { return (int)this.GetValue(MaxItemsInDropDownProperty); }
            set { this.SetValue(MaxItemsInDropDownProperty, value); }
        }

        public static readonly DependencyProperty FastLoadingACBWidthProperty =
         DependencyProperty.Register("FastLoadingACBWidth", typeof(double), typeof(FastLoadingACB), new PropertyMetadata(FastLoadingACBWidthChangedCallback));
       
        public static readonly DependencyProperty FastLoadingACBItemsSourceProperty =
         DependencyProperty.Register("FastLoadingACBItemsSource", typeof(IEnumerable), typeof(FastLoadingACB), new PropertyMetadata(FastLoadingACBItemsSourceChangedCallback));

        public static readonly DependencyProperty MaxItemsInDropDownProperty =
        DependencyProperty.Register("MaxItemsInDropDown", typeof(int), typeof(FastLoadingACB), new PropertyMetadata(10,null));

        private static void FastLoadingACBWidthChangedCallback(DependencyObject obj, DependencyPropertyChangedEventArgs e)
        {
            FastLoadingACB acb = obj as FastLoadingACB;

            if (null != acb)
                acb.acbFastLoading.Width = (double)e.NewValue;
        }

        private static void FastLoadingACBItemsSourceChangedCallback(DependencyObject obj, DependencyPropertyChangedEventArgs e)
        {
            FastLoadingACB acb = obj as FastLoadingACB;

            if (null != acb)
                acb.acbFastLoading.ItemsSource = (IEnumerable)e.NewValue;
        }

        #endregion
   
        #region Event Handlers

        private void acbFastLoading_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            if (null != FastLoadingACBSelectionChanged)
                FastLoadingACBSelectionChanged(sender, e);
        }

        private void acbFastLoading_Loaded(object sender, RoutedEventArgs e)
        {
            this.acbFastLoading.TextFilter = (search, value) =>
                {
                    if (value.Length > 0)
                    {
                        if ((this.counter < MaxItemsInDropDown) && (value.ToUpper().StartsWith(search.ToUpper()) || 
                                                                    value.ToUpper().Contains(search.ToUpper())))
                        {
                            this.counter++;
                            return true;
                        }
                        else
                            return false;
                    }
                    else
                        return false;
                };
        }

        private void acbFastLoading_TextChanged(object sender, RoutedEventArgs e)
        {
            this.counter = 0;
        }
        #endregion 
    }
}