collaborativePlatform/CollaborativePlatformMain/Form/UserControlForm/NativeCombox.xaml

<UserControl x:Class="CollaborativePlatformMain.Form.UserControlForm.NativeCombox"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:CollaborativePlatformMain.Form.UserControlForm"
        mc:Ignorable="d"
        d:DesignHeight="30" d:DesignWidth="200">
    <UserControl.Resources>
        <LinearGradientBrush x:Key="NormalBrush" StartPoint="0,0" EndPoint="0,1">
            <GradientBrush.GradientStops>
                <GradientStopCollection>
                    <GradientStop Color="White" Offset="0.0"/>
                    <GradientStop Color="White" Offset="1.0"/>
                </GradientStopCollection>
            </GradientBrush.GradientStops>
        </LinearGradientBrush>

        <LinearGradientBrush x:Key="NormalBorderBrush" StartPoint="0,0" EndPoint="0,1">
            <GradientBrush.GradientStops>
                <GradientStopCollection>
                    <GradientStop Color="White" Offset="0.0"/>
                    <GradientStop Color="White" 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="White" Offset="0.0"/>
                    <GradientStop Color="White" Offset="1.0"/>
                </GradientStopCollection>
            </GradientBrush.GradientStops>
        </LinearGradientBrush>

        <LinearGradientBrush x:Key="PressedBrush" StartPoint="0,0" EndPoint="0,1">
            <GradientBrush.GradientStops>
                <GradientStopCollection>
                    <GradientStop Color="White" Offset="0.0"/>
                    <GradientStop Color="White" Offset="0.1"/>
                    <GradientStop Color="White" Offset="0.9"/>
                    <GradientStop Color="White" Offset="1.0"/>
                </GradientStopCollection>
            </GradientBrush.GradientStops>
        </LinearGradientBrush>

        <SolidColorBrush x:Key="DisabledForegroundBrush" Color="White" />

        <SolidColorBrush x:Key="DisabledBackgroundBrush" Color="White" />

        <SolidColorBrush x:Key="WindowBackgroundBrush" Color="White" />

        <SolidColorBrush x:Key="SelectedBackgroundBrush" Color="White" />

        <SolidColorBrush x:Key="ComboBox.Static.Border" Color="White"/>

        <SolidColorBrush x:Key="ComboBox.Static.Editable.Background" Color="White"/>

        <SolidColorBrush x:Key="ComboBox.Static.Editable.Border" Color="White"/>

        <SolidColorBrush x:Key="ComboBox.Static.Editable.Button.Background" Color="Transparent"/>

        <SolidColorBrush x:Key="ComboBox.Static.Editable.Button.Border" Color="Transparent"/>

        <SolidColorBrush x:Key="ComboBox.MouseOver.Glyph" Color="White"/>

        <LinearGradientBrush x:Key="ComboBox.MouseOver.Background" EndPoint="0,1" StartPoint="0,0">
            <GradientStop Color="White" Offset="0.0"/>
            <GradientStop Color="White" Offset="1.0"/>
        </LinearGradientBrush>

        <SolidColorBrush x:Key="ComboBox.MouseOver.Border" Color="#FF7EB4EA"/>

        <SolidColorBrush x:Key="ComboBox.MouseOver.Editable.Background" Color="White"/>

        <SolidColorBrush x:Key="ComboBox.MouseOver.Editable.Border" Color="White"/>

        <LinearGradientBrush x:Key="ComboBox.MouseOver.Editable.Button.Background" EndPoint="0,1" StartPoint="0,0">
            <GradientStop Color="White" Offset="0.0"/>
            <GradientStop Color="White" Offset="1.0"/>
        </LinearGradientBrush>

        <SolidColorBrush x:Key="ComboBox.MouseOver.Editable.Button.Border" Color="White"/>

        <SolidColorBrush x:Key="ComboBox.Pressed.Glyph" Color="White"/>

        <LinearGradientBrush x:Key="ComboBox.Pressed.Background" EndPoint="0,1" StartPoint="0,0">
            <GradientStop Color="White" Offset="0.0"/>
            <GradientStop Color="White" Offset="1.0"/>
        </LinearGradientBrush>

        <SolidColorBrush x:Key="ComboBox.Pressed.Border" Color="White"/>

        <SolidColorBrush x:Key="ComboBox.Pressed.Editable.Background" Color="White"/>

        <SolidColorBrush x:Key="ComboBox.Pressed.Editable.Border" Color="White"/>

        <LinearGradientBrush x:Key="ComboBox.Pressed.Editable.Button.Background" EndPoint="0,1" StartPoint="0,0">
            <GradientStop Color="White" Offset="0.0"/>
            <GradientStop Color="White" Offset="1.0"/>
        </LinearGradientBrush>

        <SolidColorBrush x:Key="ComboBox.Pressed.Editable.Button.Border" Color="White"/>

        <SolidColorBrush x:Key="ComboBox.Disabled.Glyph" Color="White"/>

        <SolidColorBrush x:Key="ComboBox.Disabled.Background" Color="White"/>

        <SolidColorBrush x:Key="ComboBox.Disabled.Border" Color="White"/>

        <SolidColorBrush x:Key="ComboBox.Disabled.Editable.Background" Color="White"/>

        <SolidColorBrush x:Key="ComboBox.Disabled.Editable.Border" Color="White"/>

        <SolidColorBrush x:Key="ComboBox.Disabled.Editable.Button.Background" Color="Transparent"/>

        <SolidColorBrush x:Key="ComboBox.Disabled.Editable.Button.Border" Color="Transparent"/>

        <SolidColorBrush x:Key="ComboBox.Static.Glyph" Color="Black"/>

        <ControlTemplate x:Key="ComboBoxTextBox" TargetType="TextBox">
            <Border x:Name="PART_ContentHost" Focusable="False" Background="{TemplateBinding Background}" />
        </ControlTemplate>
        <Style x:Key="ComboBoxToggleButton" TargetType="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}">
                        <Border x:Name="templateRoot"  SnapsToDevicePixels="true"  Background="White">
                            <Border x:Name="splitBorder"  HorizontalAlignment="Right" Margin="0,0,2,0" SnapsToDevicePixels="true" Width="25" BorderBrush="White" BorderThickness="1,0,0,0">
                                <Path x:Name="arrow"  Data="F1 M 0,0 L 3.667,2.66665 L 7.3334,0 L 7.3334,-1.78168 L 3.6667,0.88501 L0,-1.78168 L0,0 Z" Fill="{StaticResource ComboBox.Static.Glyph}" HorizontalAlignment="Center"  VerticalAlignment="Center"/>
                            </Border>
                        </Border>
                        <ControlTemplate.Triggers>
                            <MultiDataTrigger>
                                <MultiDataTrigger.Conditions>
                                    <Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="true"/>
                                    <Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="false"/>
                                    <Condition Binding="{Binding IsPressed, RelativeSource={RelativeSource Self}}" Value="false"/>
                                    <Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="true"/>
                                </MultiDataTrigger.Conditions>
                                <Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Static.Editable.Background}"/>

                                <Setter Property="Background" TargetName="splitBorder" Value="{StaticResource ComboBox.Static.Editable.Button.Background}"/>

                            </MultiDataTrigger>
                            <Trigger Property="IsMouseOver" Value="true">
                                <Setter Property="Fill" TargetName="arrow" Value="{StaticResource ComboBox.MouseOver.Glyph}"/>
                            </Trigger>
                            <MultiDataTrigger>
                                <MultiDataTrigger.Conditions>
                                    <Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="true"/>
                                    <Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="false"/>
                                </MultiDataTrigger.Conditions>
                                <Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.MouseOver.Background}"/>

                            </MultiDataTrigger>
                            <MultiDataTrigger>
                                <MultiDataTrigger.Conditions>
                                    <Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="true"/>
                                    <Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="true"/>
                                </MultiDataTrigger.Conditions>
                                <Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.MouseOver.Editable.Background}"/>

                                <Setter Property="Background" TargetName="splitBorder" Value="{StaticResource ComboBox.MouseOver.Editable.Button.Background}"/>

                            </MultiDataTrigger>
                            <Trigger Property="IsPressed" Value="true">
                                <Setter Property="Fill" TargetName="arrow" Value="{StaticResource ComboBox.Pressed.Glyph}"/>
                            </Trigger>
                            <MultiDataTrigger>
                                <MultiDataTrigger.Conditions>
                                    <Condition Binding="{Binding IsPressed, RelativeSource={RelativeSource Self}}" Value="true"/>
                                    <Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="false"/>
                                </MultiDataTrigger.Conditions>
                                <Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Pressed.Background}"/>

                            </MultiDataTrigger>
                            <MultiDataTrigger>
                                <MultiDataTrigger.Conditions>
                                    <Condition Binding="{Binding IsPressed, RelativeSource={RelativeSource Self}}" Value="true"/>
                                    <Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="true"/>
                                </MultiDataTrigger.Conditions>
                                <Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Pressed.Editable.Background}"/>

                                <Setter Property="Background" TargetName="splitBorder" Value="{StaticResource ComboBox.Pressed.Editable.Button.Background}"/>

                            </MultiDataTrigger>
                            <Trigger Property="IsEnabled" Value="false">
                                <Setter Property="Fill" TargetName="arrow" Value="{StaticResource ComboBox.Disabled.Glyph}"/>
                            </Trigger>
                            <MultiDataTrigger>
                                <MultiDataTrigger.Conditions>
                                    <Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="false"/>
                                    <Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="false"/>
                                </MultiDataTrigger.Conditions>
                                <Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Disabled.Background}"/>

                            </MultiDataTrigger>
                            <MultiDataTrigger>
                                <MultiDataTrigger.Conditions>
                                    <Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="false"/>
                                    <Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="true"/>
                                </MultiDataTrigger.Conditions>
                                <Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Disabled.Editable.Background}"/>

                                <Setter Property="Background" TargetName="splitBorder" Value="{StaticResource ComboBox.Disabled.Editable.Button.Background}"/>

                            </MultiDataTrigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
        <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>
    <Grid Background="#aaa">
        <Border  Margin="1,1,1,1" BorderBrush="Black" CornerRadius="4,4,4,4">
            <ComboBox x:Name="CheckableCombo">
                <ComboBox.ItemTemplate>
                    <HierarchicalDataTemplate>
                        <CheckBox Content="{Binding Name}" Height="30"
                          IsChecked="{Binding IsSelect, Mode=TwoWay}"
                          Tag="{RelativeSource FindAncestor, AncestorType={x:Type ComboBox}}"
                          Click="CheckBox_Click" VerticalContentAlignment="Center" HorizontalAlignment="Left"></CheckBox>
                    </HierarchicalDataTemplate>
                </ComboBox.ItemTemplate>
                <ComboBox.Template>
                    <ControlTemplate TargetType="ComboBox">
                        <Grid>
                            <ToggleButton Name="ToggleButton" 
                                  Style="{StaticResource ComboBoxToggleButton}"
                                  Focusable="False" Click="ToggleButton_Click"
                                  IsChecked="{Binding Path=IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}">
                            </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}}">
                                    </TextBlock>
                                </ContentPresenter.Content>
                            </ContentPresenter>
                            <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="1,1,1,1" BorderBrush="White"/>
                                    <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>
        </Border>
    </Grid>
</UserControl>