<Window x:Class="WPF_25_TreeView.MainWindow"
        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:WPF_25_TreeView.Convert"
        mc:Ignorable="d" Loaded="MainWindow_OnLoaded"
        WindowStartupLocation="CenterScreen"
        Title="MainWindow1" Height="450" Width="800">

    <Grid>
        <TreeView Name="FolderView">
            <TreeView.Resources>
                <Style TargetType="{x:Type TreeViewItem}">
                    <Setter Property="HeaderTemplate">
                        <Setter.Value>
                            <DataTemplate>
                                <StackPanel Orientation="Horizontal">
                                    <Image Width="20" Height="20" Margin="3"
                                           Source="{Binding RelativeSource={
                                           RelativeSource Mode=FindAncestor,AncestorType={x:Type TreeViewItem}},
                                           Path=Tag,Converter={x:Static local:HeaderToImageConverter.Instance }}" />
                                    <TextBlock VerticalAlignment="Center" Text="{Binding}" />
                                </StackPanel>
                            </DataTemplate>
                        </Setter.Value>
                    </Setter>
                </Style>
            </TreeView.Resources>
        </TreeView>
    </Grid>
</Window>