Make own Control Checkbox in Comobobox in Wpf.

Here Sample code of Checkbox in Combobox

<Window
         …
         xmlns:controls="clr-namespace:Controls;assembly=Controls"

<controls:ComboWithCheckboxes

    x:Name="cbLanguages"

    Height="22"

    DefaultText="Choose Subtitles..."

    ItemsSource="{Binding}"

    />

XAML Code:
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<UserControl x:Class="HTBookSystem.Control.ComboWithCheckboxes"

             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"

             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"

             mc:Ignorable="d"

             Height="22" Width="120"

             x:Name="UserControl">

    <UserControl.Resources>

        <LinearGradientBrush x:Key="NormalBrush" StartPoint="0,0" EndPoint="0,1">

            <GradientBrush.GradientStops>

                <GradientStopCollection>

                    <GradientStop Color="#FFF" Offset="0.0"/>

                    <GradientStop Color="#CCC" Offset="1.0"/>

                </GradientStopCollection>

            </GradientBrush.GradientStops>

        </LinearGradientBrush>

        <LinearGradientBrush x:Key="NormalBorderBrush" StartPoint="0,0" EndPoint="0,1">

            <GradientBrush.GradientStops>

                <GradientStopCollection>

                    <GradientStop Color="#CCC" Offset="0.0"/>

                    <GradientStop Color="#444" Offset="1.0"/>

                </GradientStopCollection>

            </GradientBrush.GradientStops>

        </LinearGradientBrush>

        <SolidColorBrush x:Key="GlyphBrush" Color="#444" />

        <LinearGradientBrush x:Key="DarkBrush" StartPoint="0,0" EndPoint="0,1">

            <GradientBrush.GradientStops>

                <GradientStopCollection>

                    <GradientStop Color="#FFF" Offset="0.0"/>

                    <GradientStop Color="#AAA" Offset="1.0"/>

                </GradientStopCollection>

            </GradientBrush.GradientStops>

        </LinearGradientBrush>

        <LinearGradientBrush x:Key="PressedBrush" StartPoint="0,0" EndPoint="0,1">

            <GradientBrush.GradientStops>

                <GradientStopCollection>

                    <GradientStop Color="#BBB" Offset="0.0"/>

                    <GradientStop Color="#EEE" Offset="0.1"/>

                    <GradientStop Color="#EEE" Offset="0.9"/>

                    <GradientStop Color="#FFF" Offset="1.0"/>

                </GradientStopCollection>

            </GradientBrush.GradientStops>

        </LinearGradientBrush>

        <SolidColorBrush x:Key="DisabledForegroundBrush" Color="#888" />

        <SolidColorBrush x:Key="DisabledBackgroundBrush" Color="#EEE" />

        <SolidColorBrush x:Key="WindowBackgroundBrush" Color="#FFF" />

        <SolidColorBrush x:Key="SelectedBackgroundBrush" Color="#DDD" />

        <ControlTemplate x:Key="ComboBoxToggleButton" TargetType="ToggleButton">

            <Grid>

                <Grid.ColumnDefinitions>

                    <ColumnDefinition />

                    <ColumnDefinition Width="20" />

                </Grid.ColumnDefinitions>

                <Border

                  x:Name="Border"

                  Grid.ColumnSpan="2"

                  CornerRadius="2"

                  Background="{StaticResource NormalBrush}"

                  BorderBrush="{StaticResource NormalBorderBrush}"

                  BorderThickness="1" />

                <Border

                  Grid.Column="0"

                  CornerRadius="2,0,0,2"

                  Margin="1"

                  Background="{StaticResource WindowBackgroundBrush}"

                  BorderBrush="{StaticResource NormalBorderBrush}"

                  BorderThickness="0,0,1,0" />

                <Path

                  x:Name="Arrow"

                  Grid.Column="1"    

                  Fill="{StaticResource GlyphBrush}"

                  HorizontalAlignment="Center"

                  VerticalAlignment="Center"

                  Data="M 0 0 L 4 4 L 8 0 Z"/>

            </Grid>

            <ControlTemplate.Triggers>

                <Trigger Property="ToggleButton.IsMouseOver" Value="true">

                    <Setter TargetName="Border" Property="Background" Value="{StaticResource DarkBrush}" />

                </Trigger>

                <Trigger Property="ToggleButton.IsChecked" Value="true">

                    <Setter TargetName="Border" Property="Background" Value="{StaticResource PressedBrush}" />

                </Trigger>

                <Trigger Property="IsEnabled" Value="False">

                    <Setter TargetName="Border" Property="Background" Value="{StaticResource DisabledBackgroundBrush}" />

                    <Setter TargetName="Border" Property="BorderBrush" Value="{StaticResource DisabledBorderBrush}" />

                    <Setter Property="Foreground" Value="{StaticResource DisabledForegroundBrush}"/>

                    <Setter TargetName="Arrow" Property="Fill" Value="{StaticResource DisabledForegroundBrush}" />

                </Trigger>

            </ControlTemplate.Triggers>

        </ControlTemplate>

        <ControlTemplate x:Key="ComboBoxTextBox" TargetType="TextBox">

            <Border x:Name="PART_ContentHost" Focusable="False" Background="{TemplateBinding Background}" />

        </ControlTemplate>

        <Style x:Key="{x:Type ComboBoxItem}" TargetType="ComboBoxItem">

            <Setter Property="SnapsToDevicePixels" Value="true"/>

            <Setter Property="OverridesDefaultStyle" Value="true"/>

            <Setter Property="Template">

                <Setter.Value>

                    <ControlTemplate TargetType="ComboBoxItem">

                        <Border

                          Name="Border"

                          Padding="2"

                          SnapsToDevicePixels="true">

                            <ContentPresenter />

                        </Border>

                        <ControlTemplate.Triggers>

                            <Trigger Property="IsHighlighted" Value="true">

                                <Setter TargetName="Border" Property="Background" Value="{StaticResource SelectedBackgroundBrush}"/>

                            </Trigger>

                            <Trigger Property="IsEnabled" Value="false">

                                <Setter Property="Foreground" Value="{StaticResource DisabledForegroundBrush}"/>

                            </Trigger>

                        </ControlTemplate.Triggers>

                    </ControlTemplate>

                </Setter.Value>

            </Setter>

        </Style>

    </UserControl.Resources>

    <ComboBox

        x:Name="CheckableCombo"

        SnapsToDevicePixels="True"

        OverridesDefaultStyle="True"

        ScrollViewer.HorizontalScrollBarVisibility="Auto"

        ScrollViewer.VerticalScrollBarVisibility="Auto"

        ScrollViewer.CanContentScroll="True"

        IsSynchronizedWithCurrentItem="True"

        MinWidth="120"

        MinHeight="20"

        ItemsSource="{Binding ElementName=UserControl, Path=ItemsSource}"

        DataContext="{Binding ElementName=UserControl, Path=DataContext}"

        >

        <ComboBox.ItemTemplate>

            <HierarchicalDataTemplate>

                <CheckBox Content="{Binding Title}"

                          IsChecked="{Binding Path=IsSelected, Mode=TwoWay}"

                          Tag="{RelativeSource FindAncestor, AncestorType={x:Type ComboBox}}"

                          Click="CheckBox_Click"

                          />

            </HierarchicalDataTemplate>

        </ComboBox.ItemTemplate>

        <ComboBox.Template>

            <ControlTemplate TargetType="ComboBox">

                <Grid>

                    <ToggleButton

                        Name="ToggleButton"

                        Template="{StaticResource ComboBoxToggleButton}"

                        Grid.Column="2"

                        Focusable="false"

                        IsChecked="{Binding Path=IsDropDownOpen,Mode=TwoWay,RelativeSource={RelativeSource TemplatedParent}}"

                        ClickMode="Press">

                    </ToggleButton>

                    <ContentPresenter

                        x:Name="Presenter"

                        IsHitTestVisible="False"

                        Margin="3,3,23,3"

                        VerticalAlignment="Center"

                        HorizontalAlignment="Left">

                        <ContentPresenter.Content>

                            <TextBlock TextTrimming="CharacterEllipsis"

                                       Text="{Binding Path=Text,Mode=TwoWay,RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=UserControl}}" />

                        </ContentPresenter.Content>

                    </ContentPresenter>

                    <!-- Content="{TemplateBinding SelectionBoxItem}" -->

                    <TextBox x:Name="EditableTextBox"

                        Style="{x:Null}"

                        Template="{StaticResource ComboBoxTextBox}"

                        HorizontalAlignment="Left"

                        VerticalAlignment="Center"

                        Margin="3,3,23,3"

                        Focusable="True"

                        Background="Transparent"

                        Visibility="Hidden"

                        IsReadOnly="{TemplateBinding IsReadOnly}"/>

                    <Popup

                        Name="Popup"

                        Placement="Bottom"

                        IsOpen="{TemplateBinding IsDropDownOpen}"

                        AllowsTransparency="True"

                        Focusable="False"

                        PopupAnimation="Slide">

                        <Grid

                                  Name="DropDown"

                                  SnapsToDevicePixels="True"               

                                  MinWidth="{TemplateBinding ActualWidth}"

                                  MaxHeight="{TemplateBinding MaxDropDownHeight}">

                            <Border

                                    x:Name="DropDownBorder"

                                    Background="{StaticResource WindowBackgroundBrush}"

                                    BorderThickness="1"

                                    BorderBrush="{StaticResource SolidBorderBrush}"/>

                            <ScrollViewer Margin="4,6,4,6" SnapsToDevicePixels="True" DataContext="{Binding}">

                                <StackPanel IsItemsHost="True" KeyboardNavigation.DirectionalNavigation="Contained" />

                            </ScrollViewer>

                        </Grid>

                    </Popup>

                </Grid>

                <ControlTemplate.Triggers>

                    <Trigger Property="HasItems" Value="false">

                        <Setter TargetName="DropDownBorder" Property="MinHeight" Value="95"/>

                    </Trigger>

                    <Trigger Property="IsEnabled" Value="false">

                        <Setter Property="Foreground" Value="{StaticResource DisabledForegroundBrush}"/>

                    </Trigger>

                    <Trigger Property="IsGrouping" Value="true">

                        <Setter Property="ScrollViewer.CanContentScroll" Value="false"/>

                    </Trigger>

                    <Trigger SourceName="Popup" Property="Popup.AllowsTransparency" Value="true">

                        <Setter TargetName="DropDownBorder" Property="CornerRadius" Value="4"/>

                        <Setter TargetName="DropDownBorder" Property="Margin" Value="0,2,0,0"/>

                    </Trigger>

                    <Trigger Property="IsEditable"

                   Value="true">

                        <Setter Property="IsTabStop" Value="false"/>

                        <Setter TargetName="EditableTextBox" Property="Visibility"    Value="Visible"/>

                        <Setter TargetName="Presenter" Property="Visibility" Value="Hidden"/>

                    </Trigger>

                </ControlTemplate.Triggers>

            </ControlTemplate>

        </ComboBox.Template>

    </ComboBox>

</UserControl>

C#code:
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public partial class ComboWithCheckboxes : UserControl

    {

        public ComboWithCheckboxes()

        {

            InitializeComponent();

        }

         public object ItemsSource

        {

            get{ return(object)GetValue(ItemsSourceProperty); }

            set

           {

                SetValue(ItemsSourceProperty, value);

                SetText();

            }

        }

        public static readonly DependencyProperty ItemsSourceProperty =

       

            DependencyProperty.Register("ItemsSource", typeof(object), typeof(ComboWithCheckboxes), new UIPropertyMetadata(null));

        

        /// <summary>

        ///Gets or sets the text displayed in the ComboBox

       /// </summary>

       public string Text

        {

            get{ return(string)GetValue(TextProperty); }

            set{ SetValue(TextProperty, value); }

        }

        public static readonly DependencyProperty TextProperty =

            DependencyProperty.Register("Text", typeof(string), typeof(ComboWithCheckboxes), new UIPropertyMetadata(string.Empty));

        /// <summary>

        ///Gets or sets the text displayed in the ComboBox if there are no selected items

       /// </summary>

       public string DefaultText

        {

            get{ return(string)GetValue(DefaultTextProperty); }

            set{ SetValue(DefaultTextProperty, value); }

        }

        // Using a DependencyProperty as the backing store for DefaultText.  This enables animation, styling, binding, etc…

       public static readonly DependencyProperty DefaultTextProperty =

            DependencyProperty.Register("DefaultText", typeof(string), typeof(ComboWithCheckboxes), new UIPropertyMetadata(string.Empty));

    

        ////publicComboWithCheckboxes()

        ////{

        ////    InitializeComponent();

        ////}

        /// <summary>

        ///Whenever a CheckBox is checked, change the text displayed

       /// </summary>

        /// <param name="sender"></param>

        /// <param name="e"></param>

       private void CheckBox_Click(object sender, RoutedEventArgs e)

        {

            SetText();

        }

        /// <summary>

        ///Set the text property of this control (bound to the ContentPresenter of the ComboBox)

       /// </summary>

       private void SetText()

        {

            this.Text = (this.ItemsSource != null) ?

                this.ItemsSource.ToString() : this.DefaultText;

            // set DefaultText if nothing else selected

           if(string.IsNullOrEmpty(this.Text))

            {

                this.Text = this.DefaultText;

            }

        }

}