public class RegionConverter : IValueConverter    {        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)        {            var name = value as string;            var filter = parameter as string;            if (string.IsNullOrEmpty(name) && filter != "country")            {                return null;            }            var provider = new XmlDataProvider();            provider.Source = new Uri("Resources/Region.xml", UriKind.Relative);            if (filter == "country")            {                provider.XPath = "/region/country/@name";            }            else if (filter == "province")            {                provider.XPath = string.Format("/region/country[@name=‘{0}‘]/province/@name", name);            }            else if (filter == "city")            {                provider.XPath = string.Format("/region/country/province[@name=‘{0}‘]/city/@name", name);            }            else if (filter == "town")            {                provider.XPath = string.Format("/region/country/province/city[@name=‘{0}‘]/town/@name", name);            }            return provider;        }        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)        {            throw new NotImplementedException();        }    }

 <converters:RegionConverter x:Key="region"/>

  <ComboBox Grid.Column="0" x:Name="country"                                       DataContext="{Binding Converter={StaticResource region}, ConverterParameter=country}"                                       SelectedValue="{Binding DataContext.CurrEditorItem.Country,UpdateSourceTrigger=PropertyChanged,                                      RelativeSource={RelativeSource AncestorType={x:Type mui:ModernWindow}}}"                                      ItemsSource="{Binding}"                                       Width="85" Style="{StaticResource CommonComboBoxStyle}" />                            <ComboBox Grid.Column="2" x:Name="province"                                       DataContext="{Binding SelectedValue, ElementName=country, Converter={StaticResource region}, ConverterParameter=province}"                                       SelectedValue="{Binding DataContext.CurrEditorItem.Province,UpdateSourceTrigger=PropertyChanged,RelativeSource={RelativeSource AncestorType={x:Type mui:ModernWindow}}}"                                       ItemsSource="{Binding}"                                       Width="85" Style="{StaticResource CommonComboBoxStyle}" />                            <ComboBox Grid.Column="4" x:Name="city"                                       DataContext="{Binding SelectedValue, ElementName=province, Converter={StaticResource region}, ConverterParameter=city}"                                       SelectedValue="{Binding DataContext.CurrEditorItem.City,UpdateSourceTrigger=PropertyChanged,RelativeSource={RelativeSource AncestorType={x:Type mui:ModernWindow}}}"                                       ItemsSource="{Binding}"                                        Width="85" Style="{StaticResource CommonComboBoxStyle}" />                            <ComboBox Grid.Column="6" x:Name="town"                                       DataContext="{Binding SelectedValue, ElementName=city, Converter={StaticResource region}, ConverterParameter=town}"                                       SelectedValue="{Binding DataContext.CurrEditorItem.Area,UpdateSourceTrigger=PropertyChanged,RelativeSource={RelativeSource AncestorType={x:Type mui:ModernWindow}}}"                                       ItemsSource="{Binding}" Text="{Binding Area,UpdateSourceTrigger=PropertyChanged}"                                       Width="85" Style="{StaticResource CommonComboBoxStyle}" />                            <TextBlock Grid.Column="0" Text="国家" Tag="{Binding SelectedValue, ElementName=country}"                                        Style="{StaticResource TipTextBlock}"/>                            <TextBlock Grid.Column="2" Text="省份" Tag="{Binding SelectedValue, ElementName=province}"                                        Style="{StaticResource TipTextBlock}"/>                            <TextBlock Grid.Column="4" Text="市/区" Tag="{Binding SelectedValue, ElementName=city}"                                        Style="{StaticResource TipTextBlock}"/>                            <TextBlock Grid.Column="6" Text="县/镇" Tag="{Binding SelectedValue, ElementName=town}"                                        Style="{StaticResource TipTextBlock}"/>

  <Style x:Key="TipTextBlock" TargetType="{x:Type TextBlock}">            <Setter Property="IsHitTestVisible" Value=http://www.mamicode.com/"False" />            <Setter Property="HorizontalAlignment" Value=http://www.mamicode.com/"Left"/>            <Setter Property="VerticalAlignment" Value=http://www.mamicode.com/"Center"/>            <Setter Property="Margin" Value=http://www.mamicode.com/"12,0,0,0"/>            <Setter Property="Opacity" Value=http://www.mamicode.com/"0"/>            <Style.Triggers>                <Trigger Property="Tag" Value=http://www.mamicode.com/"{x:Null}">                    <Setter Property="Opacity" Value=http://www.mamicode.com/"1"/>                </Trigger>            </Style.Triggers>        </Style>

  <ComboBox x:Name="cbbDataType" ItemsSource="{Binding Source={StaticResource InfoDetailTypeItems}}"                      SelectedItem="{Binding CurrEditorItem.DataType, ValidatesOnDataErrors=True}"                      ItemTemplate="{StaticResource InfoDetailTypeDataTemplate}"                      Grid.Row="2" Grid.Column="1"                      Style="{StaticResource EditorComboBoxStyle}" />

  <x:Array x:Key="InfoDetailTypeItems" Type="{x:Type adservice:ShowDataType}">        <adservice:ShowDataType>Image</adservice:ShowDataType>        <adservice:ShowDataType>Video</adservice:ShowDataType>        <adservice:ShowDataType>ThreeDModel</adservice:ShowDataType>    </x:Array>