wpf 自动完成comboxBox

样式：

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                     xmlns:local="clr-namespace:MCE.Gems.Common.Controls.CustomControls"
                       xmlns:Themes="clr-namespace:Microsoft.Windows.Themes;assembly=PresentationFramework.Aero" 
                    >
    <Style x:Key="ComboBoxFocusVisual">
        <Setter Property="Control.Template">
            <Setter.Value>
                <ControlTemplate>
                    <Rectangle Margin="4,4,21,4" SnapsToDevicePixels="true" Stroke="Black" StrokeThickness="1" StrokeDashArray="1 2"/>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
    <LinearGradientBrush x:Key="ButtonNormalBackground" EndPoint="0,1" StartPoint="0,0">
        <GradientStop Color="#F3F3F3" Offset="0"/>
        <GradientStop Color="#EBEBEB" Offset="0.5"/>
        <GradientStop Color="#DDDDDD" Offset="0.5"/>
        <GradientStop Color="#CDCDCD" Offset="1"/>
    </LinearGradientBrush>
    <SolidColorBrush x:Key="ButtonNormalBorder" Color="#FF707070"/>
    <Geometry x:Key="DownArrowGeometry">M 0 0 L 3.5 4 L 7 0 Z</Geometry>
    <Style x:Key="ComboBoxReadonlyToggleButton" TargetType="{x:Type ToggleButton}">
        <Setter Property="OverridesDefaultStyle" Value="true"/>
        <Setter Property="IsTabStop" Value="false"/>
        <Setter Property="Focusable" Value="false"/>
        <Setter Property="ClickMode" Value="Press"/>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type ToggleButton}">
                    <Themes:ButtonChrome x:Name="Chrome" BorderBrush="{TemplateBinding BorderBrush}" Background="{TemplateBinding Background}" RenderMouseOver="{TemplateBinding IsMouseOver}" RenderPressed="{TemplateBinding IsPressed}" SnapsToDevicePixels="true">
                        <Grid HorizontalAlignment="Right" Width="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}">
                            <Path x:Name="Arrow" Data="{StaticResource DownArrowGeometry}" Fill="Black" HorizontalAlignment="Center" Margin="3,1,0,0" VerticalAlignment="Center"/>
                        </Grid>
                    </Themes:ButtonChrome>
                    <ControlTemplate.Triggers>
                        <Trigger Property="IsChecked" Value="true">
                            <Setter Property="RenderPressed" TargetName="Chrome" Value="true"/>
                        </Trigger>
                        <Trigger Property="IsEnabled" Value="false">
                            <Setter Property="Fill" TargetName="Arrow" Value="#AFAFAF"/>
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
    <LinearGradientBrush x:Key="TextBoxBorder" EndPoint="0,20" MappingMode="Absolute" StartPoint="0,0">
        <GradientStop Color="#ABADB3" Offset="0.05"/>
        <GradientStop Color="#E2E3EA" Offset="0.07"/>
        <GradientStop Color="#E3E9EF" Offset="1"/>
    </LinearGradientBrush>
    <Style x:Key="ComboBoxEditableTextBox" TargetType="{x:Type TextBox}">
        <Setter Property="OverridesDefaultStyle" Value="true"/>
        <Setter Property="AllowDrop" Value="true"/>
        <Setter Property="MinWidth" Value="0"/>
        <Setter Property="MinHeight" Value="0"/>
        <Setter Property="FocusVisualStyle" Value="{x:Null}"/>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type TextBox}">
                    <ScrollViewer x:Name="PART_ContentHost" Background="Transparent" Focusable="false" HorizontalScrollBarVisibility="Hidden" VerticalScrollBarVisibility="Hidden"/>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
    <Style x:Key="ComboBoxToggleButton1" TargetType="{x:Type ToggleButton}">
        <Setter Property="OverridesDefaultStyle" Value="true"/>
        <Setter Property="IsTabStop" Value="false"/>
        <Setter Property="Focusable" Value="false"/>
        <Setter Property="ClickMode" Value="Press"/>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type ToggleButton}">
                    <Grid>
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition />
                            <ColumnDefinition Width="20" />
                        </Grid.ColumnDefinitions>
                        <Border x:Name="Border" Grid.ColumnSpan="2" CornerRadius="5" Background="#ffffff" BorderBrush="#5d7fad" BorderThickness="0" SnapsToDevicePixels="True" />
                        <!-- here the Background color #e3edfd used for the righthad side Arrow background -->
                        <Border x:Name="Border1" Grid.Column="0" CornerRadius="5" Margin="1,1,1,1" Background="Transparent" BorderBrush="#5d7fad" BorderThickness="0,0,0,0" SnapsToDevicePixels="True" />
                        <!-- here the Background color #ffffff used for the Combobx -->
                        <Path x:Name="Arrow" Grid.Column="1"  Fill="#5d7fad" HorizontalAlignment="Center" VerticalAlignment="Center" Data="M 0 0 L 4 4 L 8 0 Z" SnapsToDevicePixels="True"/>
                    </Grid>

                    <ControlTemplate.Triggers>
                        <Trigger Property="IsEnabled" Value="False">
                            <Setter TargetName="Border" Property="Background" Value="#F4F4F4" />
                            <Setter TargetName="Border1" Property="Background" Value="#F4F4F4" />
                            <Setter TargetName="Border" Property="BorderBrush" Value="#5d7fad" />
                            <Setter Property="Foreground" Value="#8f8f8f"/>
                            <Setter TargetName="Arrow" Property="Fill" Value="#9F9F9F" />

                        </Trigger>
                        <Trigger Property="IsFocused" Value="True">
                            <Setter TargetName="Border" Property="BorderBrush" Value="#5d7fad" />
                            <!-- here the Background color #d4dbe3 used for the righthad side Arrow background -->
                            <Setter TargetName="Border" Property="BorderThickness" Value="1" />
                        </Trigger>

                        <Trigger Property="Validation.HasError" Value="True">
                            <Setter Property="ToolTip" Value="{Binding RelativeSource={x:Static RelativeSource.Self}, Path=(Validation.Errors)[0].ErrorContent}"/>
                            <Setter Property="Control.BorderBrush" Value="Red" />
                            <Setter Property="Control.BorderThickness" Value="1" />

                        </Trigger>

                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
    <ControlTemplate x:Key="ComboBoxEditableTemplate" TargetType="{x:Type local:AutoCompleteComboBox}">
        <Border CornerRadius="5"  Background="#FFFFFF" BorderBrush="#5d7fad" BorderThickness="1" SnapsToDevicePixels="True" >
            <Grid x:Name="Placement" SnapsToDevicePixels="true">
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="*"/>
                    <ColumnDefinition Width="Auto"/>
                </Grid.ColumnDefinitions>

                <Popup x:Name="PART_Popup" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{DynamicResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                    <Themes:SystemDropShadowChrome x:Name="Shdw" Color="Transparent" MaxHeight="{TemplateBinding MaxDropDownHeight}" MinWidth="{Binding ActualWidth, ElementName=Placement}">
                        <Border x:Name="DropDownBorder" Background="#FFFFFF" BorderThickness="1" CornerRadius="5" BorderBrush="#5d7fad">
                            <ScrollViewer Margin="4" SnapsToDevicePixels="True">
                                <ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
                            </ScrollViewer>
                        </Border>
                    </Themes:SystemDropShadowChrome>
                </Popup>
                <Themes:ListBoxChrome x:Name="Border" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" RenderMouseOver="{TemplateBinding IsMouseOver}" RenderFocused="{TemplateBinding IsKeyboardFocusWithin}"/>
                <TextBox x:Name="PART_EditableTextBox" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" IsReadOnly="{Binding IsReadOnly, RelativeSource={RelativeSource TemplatedParent}}" Margin="{TemplateBinding Padding}" Style="{StaticResource ComboBoxEditableTextBox}" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"/>
                <ToggleButton Grid.Column="1" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxToggleButton1}"/>
            </Grid>
        </Border>

        <ControlTemplate.Triggers>
            <Trigger Property="IsKeyboardFocusWithin" Value="true">
                <Setter Property="Foreground" Value="Black"/>
            </Trigger>
            <Trigger Property="IsDropDownOpen" Value="true">
                <Setter Property="RenderFocused" TargetName="Border" Value="true"/>
            </Trigger>
            <Trigger Property="HasItems" Value="false">
                <Setter Property="Height" TargetName="DropDownBorder" Value="95"/>
            </Trigger>
            <Trigger Property="IsEnabled" Value="false">
                <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}"/>
                <Setter Property="Background" Value="#FFF4F4F4"/>
            </Trigger>
            <Trigger Property="IsGrouping" Value="true">
                <Setter Property="ScrollViewer.CanContentScroll" Value="false"/>
            </Trigger>
            <Trigger Property="HasDropShadow" SourceName="PART_Popup" Value="true">
                <Setter Property="Margin" TargetName="Shdw" Value="0,0,5,5"/>
                <Setter Property="Color" TargetName="Shdw" Value="#71000000"/>
            </Trigger>
        </ControlTemplate.Triggers>
    </ControlTemplate>
    <Style  TargetType="{x:Type local:AutoCompleteComboBox}">
        <Setter Property="FontSize" Value="14"/>
        <Setter Property="FontWeight" Value="Normal"/>
        <Setter Property="HorizontalAlignment" Value="Left"/>
        <Setter Property="VerticalAlignment" Value="Center"/>
        <Setter Property="VerticalContentAlignment" Value="Center"/>
        <Setter Property="SnapsToDevicePixels" Value="true"/>
        <Setter Property="OverridesDefaultStyle" Value="true"/>
        <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Auto"/>
        <Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto"/>
        <Setter Property="ScrollViewer.CanContentScroll" Value="true"/>
        <Setter Property="Height" Value="28"></Setter>
        <Setter Property="Margin" Value="0"/>
        <Setter Property="Padding" Value="5,0,5,2"></Setter>
        <Setter Property="Foreground" Value="#0c223a"/>
        <Setter Property="FontFamily" Value="Arial" />
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type local:AutoCompleteComboBox}">
                    <Grid x:Name="MainGrid" SnapsToDevicePixels="true">
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition Width="*"/>
                            <ColumnDefinition MinWidth="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}" Width="0"/>
                        </Grid.ColumnDefinitions>
                        <Popup x:Name="PART_Popup" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{DynamicResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                            <Themes:SystemDropShadowChrome x:Name="Shdw" Color="Transparent" MaxHeight="{TemplateBinding MaxDropDownHeight}" MinWidth="{Binding ActualWidth, ElementName=MainGrid}">
                                <Border x:Name="DropDownBorder" BorderBrush="{DynamicResource {x:Static SystemColors.WindowFrameBrushKey}}" BorderThickness="1" Background="{DynamicResource {x:Static SystemColors.WindowBrushKey}}">
                                    <ScrollViewer CanContentScroll="true">
                                        <ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
                                    </ScrollViewer>
                                </Border>
                            </Themes:SystemDropShadowChrome>
                        </Popup>
                        <ToggleButton BorderBrush="{TemplateBinding BorderBrush}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxReadonlyToggleButton}"/>
                        <ContentPresenter ContentTemplate="{TemplateBinding SelectionBoxItemTemplate}" ContentTemplateSelector="{TemplateBinding ItemTemplateSelector}" Content="{TemplateBinding SelectionBoxItem}" ContentStringFormat="{TemplateBinding SelectionBoxItemStringFormat}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" IsHitTestVisible="false" Margin="{TemplateBinding Padding}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
                    </Grid>
                    <ControlTemplate.Triggers>
                        <Trigger Property="HasDropShadow" SourceName="PART_Popup" Value="true">
                            <Setter Property="Margin" TargetName="Shdw" Value="0,0,5,5"/>
                            <Setter Property="Color" TargetName="Shdw" Value="#71000000"/>
                        </Trigger>
                        <Trigger Property="HasItems" Value="false">
                            <Setter Property="Height" TargetName="DropDownBorder" Value="95"/>
                        </Trigger>
                        <Trigger Property="IsEnabled" Value="false">
                            <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}"/>
                            <Setter Property="Background" Value="#FFF4F4F4"/>
                        </Trigger>
                        <Trigger Property="IsGrouping" Value="true">
                            <Setter Property="ScrollViewer.CanContentScroll" Value="false"/>
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
            
        </Setter>
        <Setter Property="Validation.ErrorTemplate">
            <Setter.Value>
                <ControlTemplate>
                    <AdornedElementPlaceholder>
                        <Border BorderBrush="Red" BorderThickness="1" CornerRadius="5" SnapsToDevicePixels="True" />

                    </AdornedElementPlaceholder>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
        <Style.Triggers>
            <Trigger Property="IsEditable" Value="true">
                <!--<Setter Property="BorderBrush" Value="{StaticResource TextBoxBorder}"/>
                    <Setter Property="Background" Value="{DynamicResource {x:Static SystemColors.WindowBrushKey}}"/>-->
                <Setter Property="IsTabStop" Value="false"/>
                <!--<Setter Property="Padding" Value="3"/>-->
                <Setter Property="Template" Value="{StaticResource ComboBoxEditableTemplate}"/>
            </Trigger>
        </Style.Triggers>
        
    </Style>

</ResourceDictionary>

三个属性注意

this.StaysOpenOnEdit = true 

this.IsEditable = true

this.IsTextSearchEnabled = false//自带的自动完成

第一种：简单的。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;

namespace GEMS.Windows.Controls.CustomControls
{
    public class SimpleAutoCompleteComboBox : ComboBox
    {
        static SimpleAutoCompleteComboBox()
        {
            DefaultStyleKeyProperty.OverrideMetadata(typeof(SimpleAutoCompleteComboBox), new FrameworkPropertyMetadata(typeof(SimpleAutoCompleteComboBox)));

        }

        public SimpleAutoCompleteComboBox()
        {
            this.StaysOpenOnEdit = true;
            this.IsEditable = true;
            this.IsTextSearchEnabled = true;
            this.LostFocus += SimpleAutoCompleteComboBox_LostFocus;
        }


        public override void OnApplyTemplate()
        {
            base.OnApplyTemplate();

            //load the text box control
            if (this.EditableTextBox != null)
            {
               // this.EditableTextBox.PreviewKeyDown += new KeyEventHandler(EditableTextBox_PreviewKeyDown);
                this.EditableTextBox.TextChanged += new TextChangedEventHandler(EditableTextBox_TextChanged);
            }
        }

        //void EditableTextBox_PreviewKeyDown(object sender, KeyEventArgs e)
        //{
        //    this.IsKeyEvent = true;
        //}

        void EditableTextBox_TextChanged(object sender, TextChangedEventArgs e)
        {
            if ( this.EditableTextBox.IsFocused)
            
            {
                this.IsDropDownOpen = true;
            }
           
        }


        /// <summary>
        /// Gets the text box in charge of the editable portion of the combo box.
        /// </summary>
        protected TextBox EditableTextBox
        {
            get
            {
                return base.GetTemplateChild("PART_EditableTextBox") as TextBox;
            }
        }

        private string SelectedText
        {
            get
            {
                if (this.SelectedIndex == -1) return string.Empty;

                return this.SelectedItem.GetType().GetProperty(this.DisplayMemberPath).GetValue(this.SelectedItem, null).ToString();
            }
        }


        void SimpleAutoCompleteComboBox_LostFocus(object sender, RoutedEventArgs e)
        {
            this.IsDropDownOpen = false;
            // to prevent misunderstanding that user has entered some information
            if (this.SelectedIndex == -1)
            {
                this.Text = null;
                this.SelectedItem = null;
                this.SelectedValue = null;
            }
            // syncronize text
            else
                this.Text = this.SelectedText;
            // release timer resources
           

            try
            {
                this.EditableTextBox.CaretIndex = 0;
            }
            catch { }
        }
    }
}

第2种：下拉只显示关联的

using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Timers;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;

namespace GEMS.Windows.Controls.CustomControls
{
    public class AutoCompleteComboBox : ComboBox
    {
        #region Fields
        private Timer _interval;
        private int _maxRecords = 10;
        private bool _typeAhead = false;
        private bool IsKeyEvent = false;
        private bool _clearOnEmpty = true;
        private int _delay = DEFAULT_DELAY;
        private const int DEFAULT_DELAY = 500;
        private ObservableCollection<dynamic> CurrentItems;
        #endregion


        #region properties

        [DefaultValue(DEFAULT_DELAY)]
        public int Delay
        {
            get
            {
                return this._delay;
            }
            set
            {
                this._delay = value;
            }
        }
        public bool ClearOnEmpty
        {
            get
            {
                return this._clearOnEmpty;
            }
            set
            {
                this._clearOnEmpty = true;
            }
        }

        /// <summary>
        /// Gets the text box in charge of the editable portion of the combo box.
        /// </summary>
        protected TextBox EditableTextBox
        {
            get
            {
                return base.GetTemplateChild("PART_EditableTextBox") as TextBox;
            }
        }

        private string SelectedText
        {
            get
            {
                if (this.SelectedIndex == -1) return string.Empty;

                return this.SelectedItem.GetType().GetProperty((string.IsNullOrWhiteSpace(this.SearchBy) ? this.DisplayMemberPath : this.SearchBy)).GetValue(this.SelectedItem, null).ToString();
            }
        }

        #endregion

        #region DependencyProperty

        public static readonly DependencyProperty DataSourceProperty =
            DependencyProperty.Register("DataSource", typeof(IEnumerable), typeof(AutoCompleteComboBox), new PropertyMetadata(null, new PropertyChangedCallback(OnDataSourceChanged)));

        private static void OnDataSourceChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            AutoCompleteComboBox autoCompleteComboBox = (AutoCompleteComboBox)d;
            autoCompleteComboBox.ItemsSource = (IEnumerable)e.NewValue;
        }


        public IEnumerable DataSource
        {
            get
            {
                return base.GetValue(AutoCompleteComboBox.DataSourceProperty) as IEnumerable;
            }
            set
            {
                base.SetValue(AutoCompleteComboBox.DataSourceProperty, value);
            }
        }


        public string SearchBy
        {
            get { return (string)GetValue(SearchByProperty); }
            set { SetValue(SearchByProperty, value); }
        }

        // Using a DependencyProperty as the backing store for SearchBy.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty SearchByProperty =
            DependencyProperty.Register("SearchBy", typeof(string), typeof(AutoCompleteComboBox), new PropertyMetadata(null));


        #endregion

        public override void OnApplyTemplate()
        {
            base.OnApplyTemplate();

            //load the text box control
            if (this.EditableTextBox != null)
            {
                this.EditableTextBox.PreviewKeyDown += new KeyEventHandler(EditableTextBox_PreviewKeyDown);
                this.EditableTextBox.TextChanged += new TextChangedEventHandler(EditableTextBox_TextChanged);
            }
        }

        static AutoCompleteComboBox()
        {
            DefaultStyleKeyProperty.OverrideMetadata(typeof(AutoCompleteComboBox), new FrameworkPropertyMetadata(typeof(AutoCompleteComboBox)));

        }
        public AutoCompleteComboBox()
        {

            CurrentItems = new ObservableCollection<dynamic>();
            if (!DesignerProperties.GetIsInDesignMode(this))
            {
                this._interval = new Timer(this.Delay);
                this._interval.AutoReset = true;
                this._interval.Elapsed += new ElapsedEventHandler(_interval_Elapsed);
            }
            this.Loaded += AutoCompleteComboBox_Loaded;
            this.LostFocus += AutoCompleteComboBox_LostFocus;
            this.SelectionChanged += AutoCompleteComboBox_SelectionChanged;
            this.StaysOpenOnEdit = true;
            this.IsEditable = true;
            this.IsTextSearchEnabled = false;
        }

        private void AutoCompleteComboBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            this._interval.Stop();
        }

        void AutoCompleteComboBox_LostFocus(object sender, RoutedEventArgs e)
        {
            this.IsKeyEvent = false;
            this.IsDropDownOpen = false;
            // to prevent misunderstanding that user has entered some information
            if (this.SelectedIndex == -1)
            {
                this.Text = null;
                this.SelectedItem = null;
                this.SelectedValue = null;
            }
            // syncronize text
            else
                this.Text = this.SelectedText;
            // release timer resources
            this._interval.Close();

            try
            {
                this.EditableTextBox.CaretIndex = 0;
            }
            catch { }
        }

        void AutoCompleteComboBox_Loaded(object sender, RoutedEventArgs e)
        {
            this.ItemsSource = this.DataSource;
        }

        #region MyRegion
        void _interval_Elapsed(object sender, ElapsedEventArgs e)
        {
            IsKeyEvent = false;
            // pause the timer
            this._interval.Stop();

            // show the drop down when user starts typing then stops
            this.Dispatcher.BeginInvoke((Action)delegate
            {

                // load from event source
                this.CurrentItems = new ObservableCollection<dynamic>();

                if (this.Text.Length >= 0)
                {

                    foreach (var entry in DataSource)
                    {

                        string SearchName = entry.GetType().GetProperty((string.IsNullOrWhiteSpace(this.SearchBy) ? this.DisplayMemberPath : this.SearchBy)).GetValue(entry, null).ToString().ToUpper();
                        if (SearchName.StartsWith(this.Text.ToUpper(), StringComparison.CurrentCultureIgnoreCase))
                        {
                            CurrentItems.Add(entry);

                        }

                    }

                    this.ItemsSource = CurrentItems;
                    this.IsDropDownOpen = this.HasItems;
                }
                else
                {
                    this.IsDropDownOpen = false;
                }

            },
                System.Windows.Threading.DispatcherPriority.ApplicationIdle);
        }
        #endregion


        #region EditableTextBoxEvent
        void EditableTextBox_PreviewKeyDown(object sender, KeyEventArgs e)
        {
            this.IsKeyEvent = true;
        }

        void EditableTextBox_TextChanged(object sender, TextChangedEventArgs e)
        {
            if ( this.EditableTextBox.IsFocused)
            {
                if (this.ClearOnEmpty && string.IsNullOrEmpty(this.EditableTextBox.Text.Trim()))
                    this.ItemsSource = this.DataSource;
                else if (IsKeyEvent)
                    this.ResetTimer();
            }
          
        }

        protected void ResetTimer()
        {
            this._interval.Stop();
            this._interval.Start();
        }

        #endregion



    }
}