the standard WPF treeview shows child items when expanded below the parent item. For a better visibility, I want to display the child-items to the right of the parent. Something like this:
The Release items are children of ReleaseLists
(How) can I achieve that?
Thanks in advance,
Frank
You cannot take out the TreeViewItem from its TreeView. Best you can do is modify its template to expand it horizontally. But then also you wont achieve desired effect, as expanded area wont float above anything else like a Popup.
So, I created a new Control deriving from Menu. A Menu is best suited for your case, as it opens its sub-menu horizontally. And never goes offscreen. A new Control was needed to override its behavior of opening sub-menu on mouse-over. We need TreeView like behavior, so expansion must happen on mouse-click and not on hover.
This control also preserves full keyboard support to navigate entire Menu using left/right/up/down/esc keys.
Drop Menu control in your window and Right Click Menu control in Document Outline > Edit Additional Templates > ItemContainerStyle . This will give you needed resources. Just Copy Paste it as it is in a new file called TreeViewFloatingDisplay.xaml like below. I have ommitted code for brevity with ... , and replaced content is shown with a comment, and new content is presented below it.
TreeViewFloatingDisplay.xaml
<Menu x:Class="WpfStackOverflow.MenuAsTreeView2.TreeViewFloatingDisplay"
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"
xmlns:Themes="clr-namespace:Microsoft.Windows.Themes;assembly=PresentationFramework.Aero"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="300">
<Menu.Resources>
<Geometry x:Key="RightArrow">M 0,0 L 4,3.5 L 0,7 Z</Geometry>
<LinearGradientBrush x:Key="MenuItemSelectionFill" EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#34C5EBFF" Offset="0"/>
<GradientStop Color="#3481D8FF" Offset="1"/>
</LinearGradientBrush>
<Geometry x:Key="Checkmark">M 0,5.1 L 1.7,5.2 L 3.4,7.1 L 8,0.4 L 9.2,0 L 3.3,10.8 Z</Geometry>
<ControlTemplate x:Key="{ComponentResourceKey ResourceId=SubmenuItemTemplateKey, TypeInTargetAssembly={x:Type MenuItem}}" TargetType="{x:Type MenuItem}">
<Grid SnapsToDevicePixels="true">
<Rectangle x:Name="Bg" Fill="{TemplateBinding Background}" RadiusY="2" RadiusX="2" Stroke="{TemplateBinding BorderBrush}" StrokeThickness="1"/>
<Rectangle x:Name="InnerBorder" Margin="1" RadiusY="2" RadiusX="2"/>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition MinWidth="14" SharedSizeGroup="MenuItemIconColumnGroup" Width="Auto"/>
<ColumnDefinition Width="4"/>
<ColumnDefinition Width="*"/>
<!--<ColumnDefinition Width="37"/>-->
<ColumnDefinition Width="0"/>
<ColumnDefinition SharedSizeGroup="MenuItemIGTColumnGroup" Width="Auto"/>
<!--<ColumnDefinition Width="17"/>-->
<ColumnDefinition Width="0"/>
</Grid.ColumnDefinitions>
<ContentPresenter x:Name="Icon" ContentSource="Icon" Margin="1" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="Center"/>
<Border x:Name="GlyphPanel" BorderBrush="#CDD3E6" BorderThickness="1" Background="#E6EFF4" CornerRadius="3" Height="22" Margin="1" Visibility="Hidden" Width="22">
<Path x:Name="Glyph" Data="{StaticResource Checkmark}" Fill="#0C12A1" FlowDirection="LeftToRight" Height="11" Width="9"/>
</Border>
<ContentPresenter Grid.Column="2" ContentSource="Header" Margin="{TemplateBinding Padding}" RecognizesAccessKey="True" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
<TextBlock Grid.Column="4" Margin="{TemplateBinding Padding}" Text="{TemplateBinding InputGestureText}"/>
</Grid>
</Grid>
<ControlTemplate.Triggers>
...
</ControlTemplate.Triggers>
</ControlTemplate>
<LinearGradientBrush x:Key="MenuItemPressedFill" EndPoint="0,1" StartPoint="0,0">
...
</LinearGradientBrush>
<SolidColorBrush x:Key="SubMenuBackgroundBrush" Color="#FFF5F5F5"/>
<Geometry x:Key="UpArrow">M 0,4 L 3.5,0 L 7,4 Z</Geometry>
<Style x:Key="MenuScrollButton" BasedOn="{x:Null}" TargetType="{x:Type RepeatButton}">
...
</Style>
<MenuScrollingVisibilityConverter x:Key="MenuScrollingVisibilityConverter"/>
<Geometry x:Key="DownArrow">M 0,0 L 3.5,4 L 7,0 Z</Geometry>
<Style x:Key="{ComponentResourceKey ResourceId=MenuScrollViewer, TypeInTargetAssembly={x:Type FrameworkElement}}" BasedOn="{x:Null}" TargetType="{x:Type ScrollViewer}">
...
</Style>
<ControlTemplate x:Key="{ComponentResourceKey ResourceId=TopLevelHeaderTemplateKey, TypeInTargetAssembly={x:Type MenuItem}}" TargetType="{x:Type MenuItem}">
<Grid SnapsToDevicePixels="true">
<Rectangle x:Name="OuterBorder" RadiusY="2" RadiusX="2"/>
<Rectangle x:Name="Bg" Fill="{TemplateBinding Background}" Margin="1" RadiusY="1" RadiusX="1" Stroke="{TemplateBinding BorderBrush}" StrokeThickness="1"/>
<Rectangle x:Name="InnerBorder" Margin="2"/>
<DockPanel>
<Path x:Name="PART_RightArrow" Data="{StaticResource RightArrow}" Fill="Transparent" Stroke="Black" Margin="8,0,0,0" VerticalAlignment="Center" HorizontalAlignment="Right"/>
<ContentPresenter Visibility="Collapsed" x:Name="Icon" ContentSource="Icon" Margin="4,0,6,0" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="Center"/>
<Path x:Name="GlyphPanel" Data="{StaticResource Checkmark}" Fill="{TemplateBinding Foreground}" FlowDirection="LeftToRight" Margin="7,0,0,0" Visibility="Collapsed" VerticalAlignment="Center"/>
<ContentPresenter ContentSource="Header" Margin="{TemplateBinding Padding}" RecognizesAccessKey="True" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
</DockPanel>
<!--<Popup x:Name="PART_Popup" AllowsTransparency="true" Focusable="false" HorizontalOffset="1" IsOpen="{Binding IsSubmenuOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{DynamicResource {x:Static SystemParameters.MenuPopupAnimationKey}}" Placement="Bottom" VerticalOffset="-1">-->
<Popup x:Name="PART_Popup" AllowsTransparency="true" Focusable="false" HorizontalOffset="1" IsOpen="{Binding IsSubmenuOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{DynamicResource {x:Static SystemParameters.MenuPopupAnimationKey}}" Placement="Right" VerticalOffset="0">
<Themes:SystemDropShadowChrome x:Name="Shdw" Color="Transparent">
<Border x:Name="SubMenuBorder" BorderBrush="#FF959595" BorderThickness="1" Background="{StaticResource SubMenuBackgroundBrush}">
<ScrollViewer x:Name="SubMenuScrollViewer" Margin="1,0" Style="{DynamicResource {ComponentResourceKey ResourceId=MenuScrollViewer, TypeInTargetAssembly={x:Type FrameworkElement}}}">
<Grid RenderOptions.ClearTypeHint="Enabled">
<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
<Rectangle x:Name="OpaqueRect" Fill="{StaticResource SubMenuBackgroundBrush}" Height="{Binding ActualHeight, ElementName=SubMenuBorder}" Width="{Binding ActualWidth, ElementName=SubMenuBorder}"/>
</Canvas>
<!-- Comment below 3 rectangles to remove vertical line present on the left -->
<!--<Rectangle Fill="#F1F1F1" HorizontalAlignment="Left" Margin="1,2" RadiusY="2" RadiusX="2" Width="28"/>
<Rectangle Fill="#E2E3E3" HorizontalAlignment="Left" Margin="29,2,0,2" Width="1"/>
<Rectangle Fill="White" HorizontalAlignment="Left" Margin="30,2,0,2" Width="1"/>-->
<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Cycle" Grid.IsSharedSizeScope="true" Margin="2" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" KeyboardNavigation.TabNavigation="Cycle"/>
</Grid>
</ScrollViewer>
</Border>
</Themes:SystemDropShadowChrome>
</Popup>
</Grid>
<ControlTemplate.Triggers>
...
</ControlTemplate.Triggers>
</ControlTemplate>
<ControlTemplate x:Key="{ComponentResourceKey ResourceId=TopLevelItemTemplateKey, TypeInTargetAssembly={x:Type MenuItem}}" TargetType="{x:Type MenuItem}">
...
</ControlTemplate>
<ControlTemplate x:Key="{ComponentResourceKey ResourceId=SubmenuHeaderTemplateKey, TypeInTargetAssembly={x:Type MenuItem}}" TargetType="{x:Type MenuItem}">
<Grid SnapsToDevicePixels="true">
<Rectangle x:Name="Bg" Fill="{TemplateBinding Background}" RadiusY="2" RadiusX="2" Stroke="{TemplateBinding BorderBrush}" StrokeThickness="1"/>
<Rectangle x:Name="InnerBorder" Margin="1" RadiusY="2" RadiusX="2" Stroke="Transparent" StrokeThickness="1"/>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition MinWidth="14" SharedSizeGroup="MenuItemIconColumnGroup" Width="Auto"/>
<ColumnDefinition Width="4"/>
<ColumnDefinition Width="*"/>
<!--<ColumnDefinition Width="37"/>-->
<ColumnDefinition Width="0"/>
<ColumnDefinition SharedSizeGroup="MenuItemIGTColumnGroup" Width="Auto"/>
<!--<ColumnDefinition Width="17"/>-->
<ColumnDefinition Width="0"/>
</Grid.ColumnDefinitions>
<ContentPresenter x:Name="Icon" ContentSource="Icon" Margin="1" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="Center"/>
<Border x:Name="GlyphPanel" BorderBrush="#CDD3E6" BorderThickness="1" Background="#E6EFF4" CornerRadius="3" Height="22" Margin="1" Visibility="Hidden" Width="22">
<Path x:Name="Glyph" Data="{StaticResource Checkmark}" Fill="#0C12A1" FlowDirection="LeftToRight" Height="11" Width="9"/>
</Border>
<ContentPresenter Grid.Column="2" ContentSource="Header" Margin="{TemplateBinding Padding}" RecognizesAccessKey="True" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
<TextBlock Grid.Column="4" Margin="{TemplateBinding Padding}" Text="{TemplateBinding InputGestureText}" Visibility="Collapsed"/>
<!--<Path Grid.Column="5" Data="{StaticResource RightArrow}" Fill="{TemplateBinding Foreground}" Margin="4,0,0,0" VerticalAlignment="Center"/>-->
<Path Grid.Column="0" x:Name="PART_RightArrow" Data="{StaticResource RightArrow}" Fill="Transparent" Stroke="Black" Margin="4,0,0,0" VerticalAlignment="Center" HorizontalAlignment="Center"/>
</Grid>
<!--<Popup x:Name="PART_Popup" AllowsTransparency="true" Focusable="false" HorizontalOffset="-2" IsOpen="{Binding IsSubmenuOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{DynamicResource {x:Static SystemParameters.MenuPopupAnimationKey}}" Placement="Right" VerticalOffset="-3">-->
<Popup x:Name="PART_Popup" AllowsTransparency="true" Focusable="false" HorizontalOffset="3" IsOpen="{Binding IsSubmenuOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{DynamicResource {x:Static SystemParameters.MenuPopupAnimationKey}}" Placement="Right" VerticalOffset="-4">
<Themes:SystemDropShadowChrome x:Name="Shdw" Color="Transparent">
<Border x:Name="SubMenuBorder" BorderBrush="#FF959595" BorderThickness="1" Background="{StaticResource SubMenuBackgroundBrush}">
<ScrollViewer x:Name="SubMenuScrollViewer" Margin="1,0" Style="{DynamicResource {ComponentResourceKey ResourceId=MenuScrollViewer, TypeInTargetAssembly={x:Type FrameworkElement}}}">
<Grid RenderOptions.ClearTypeHint="Enabled">
<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
<Rectangle x:Name="OpaqueRect" Fill="{StaticResource SubMenuBackgroundBrush}" Height="{Binding ActualHeight, ElementName=SubMenuBorder}" Width="{Binding ActualWidth, ElementName=SubMenuBorder}"/>
</Canvas>
<!-- Comment below 3 rectangles to remove vertical line present on the left -->
<!--<Rectangle Fill="#F1F1F1" HorizontalAlignment="Left" Margin="1,2" RadiusY="2" RadiusX="2" Width="28"/>
<Rectangle Fill="#E2E3E3" HorizontalAlignment="Left" Margin="29,2,0,2" Width="1"/>
<Rectangle Fill="White" HorizontalAlignment="Left" Margin="30,2,0,2" Width="1"/>-->
<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Cycle" Grid.IsSharedSizeScope="true" Margin="2" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" KeyboardNavigation.TabNavigation="Cycle"/>
</Grid>
</ScrollViewer>
</Border>
</Themes:SystemDropShadowChrome>
</Popup>
</Grid>
<ControlTemplate.Triggers>
...
</ControlTemplate.Triggers>
</ControlTemplate>
<Style x:Key="MenuItemStyle1" TargetType="{x:Type MenuItem}">
<Setter Property="HorizontalContentAlignment" Value="{Binding HorizontalContentAlignment, RelativeSource={RelativeSource AncestorType={x:Type ItemsControl}}}"/>
<Setter Property="VerticalContentAlignment" Value="{Binding VerticalContentAlignment, RelativeSource={RelativeSource AncestorType={x:Type ItemsControl}}}"/>
<Setter Property="Background" Value="Transparent"/>
<Setter Property="ScrollViewer.PanningMode" Value="Both"/>
<Setter Property="Stylus.IsFlicksEnabled" Value="False"/>
<Setter Property="Template" Value="{DynamicResource {ComponentResourceKey ResourceId=SubmenuItemTemplateKey, TypeInTargetAssembly={x:Type MenuItem}}}"/>
<Style.Triggers>
<Trigger Property="Role" Value="TopLevelHeader">
<Setter Property="Padding" Value="7,2,8,3"/>
<Setter Property="Template" Value="{DynamicResource {ComponentResourceKey ResourceId=TopLevelHeaderTemplateKey, TypeInTargetAssembly={x:Type MenuItem}}}"/>
</Trigger>
<Trigger Property="Role" Value="TopLevelItem">
<Setter Property="Padding" Value="7,2,8,3"/>
<Setter Property="Template" Value="{DynamicResource {ComponentResourceKey ResourceId=TopLevelItemTemplateKey, TypeInTargetAssembly={x:Type MenuItem}}}"/>
</Trigger>
<Trigger Property="Role" Value="SubmenuHeader">
<!--<Setter Property="Padding" Value="2,3,2,3"/>-->
<Setter Property="Padding" Value="1,2,1,2"/>
<Setter Property="Template" Value="{DynamicResource {ComponentResourceKey ResourceId=SubmenuHeaderTemplateKey, TypeInTargetAssembly={x:Type MenuItem}}}"/>
</Trigger>
<Trigger Property="Role" Value="SubmenuItem">
<!--<Setter Property="Padding" Value="2,3,2,3"/>-->
<Setter Property="Padding" Value="1,2,1,2"/>
</Trigger>
</Style.Triggers>
</Style>
</Menu.Resources>
</Menu>
TreeViewFloatingDisplay.xaml.cs
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Shapes;
using System.Windows.Threading;
namespace WpfStackOverflow.MenuAsTreeView2
{
/// <summary>
/// Interaction logic for TreeViewFloatingDisplay.xaml
/// </summary>
public partial class TreeViewFloatingDisplay : Menu
{
public TreeViewFloatingDisplay()
{
InitializeComponent();
}
protected override DependencyObject GetContainerForItemOverride()
{
return new MenuItemNew();
}
}
public class MenuItemNew : MenuItem
{
#region Constructors
static MenuItemNew()
{
MenuItem.IsSubmenuOpenProperty.OverrideMetadata(typeof(MenuItemNew),
new FrameworkPropertyMetadata(false, MenuItem.IsSubmenuOpenProperty.DefaultMetadata.PropertyChangedCallback, CoerceIsSubmenuOpen));
}
public MenuItemNew()
{
this.PreviewMouseLeftButtonDown += MenuItemNew_PreviewMouseLeftButtonDown;
}
#endregion
#region Event Handlers
void MenuItemNew_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
MenuItemNew curItem = sender as MenuItemNew;
System.Diagnostics.Debug.WriteLine("Role = " + curItem.Role);
Path pth = e.OriginalSource as Path;
if (pth == null) return;
DependencyObject parent = VisualTreeHelper.GetParent(pth);
while (parent as MenuItemNew == null)
parent = VisualTreeHelper.GetParent(parent);
MenuItemNew actualSource = parent as MenuItemNew;
if (actualSource.Role == MenuItemRole.TopLevelHeader)
{
IsExpanderClicked = !IsExpanderClicked;
actualSource.CoerceValue(MenuItemNew.IsSubmenuOpenProperty);
}
if (curItem.Role == MenuItemRole.SubmenuHeader)
{
IsExpanderClicked = !IsExpanderClicked;
curItem.CoerceValue(MenuItemNew.IsSubmenuOpenProperty);
}
}
#endregion
#region IsExpanderClicked Dependency Property
public bool IsExpanderClicked
{
get { return (bool)GetValue(IsExpanderClickedProperty); }
set { SetValue(IsExpanderClickedProperty, value); }
}
// Using a DependencyProperty as the backing store for IsExpanderClicked. This enables animation, styling, binding, etc...
public static readonly DependencyProperty IsExpanderClickedProperty =
DependencyProperty.Register("IsExpanderClicked", typeof(bool), typeof(MenuItemNew), new PropertyMetadata(false));
#endregion
#region Overrides
protected override DependencyObject GetContainerForItemOverride()
{
return new MenuItemNew();
}
#endregion
#region Dependency Property Callbacks
private static object CoerceIsSubmenuOpen(DependencyObject d, object value)
{
MenuItemNew item = (MenuItemNew)d;
if ((bool)value)
{
if (item.IsMouseOver)
{
System.Diagnostics.Debug.WriteLine(item.IsExpanderClicked.ToString());
return item.IsExpanderClicked;
}
if (!item.IsLoaded)
{
item.Loaded += (s, e) =>
{
Application.Current.Dispatcher.BeginInvoke(DispatcherPriority.Input, new DispatcherOperationCallback(delegate(object param)
{
item.CoerceValue(MenuItemNew.IsSubmenuOpenProperty);
return null;
}), null);
};
return false;
}
}
if (item.IsExpanderClicked)
return true;
return value;
}
#endregion
}
}
Usage
<Grid>
<myMenu:TreeViewFloatingDisplay Background="AliceBlue" ItemsSource="{Binding Countries}" Width="300" HorizontalAlignment="Left">
<myMenu:TreeViewFloatingDisplay.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel/>
</ItemsPanelTemplate>
</myMenu:TreeViewFloatingDisplay.ItemsPanel>
<myMenu:TreeViewFloatingDisplay.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding States}">
<HierarchicalDataTemplate.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding Cities}">
<Grid>
<ContentControl Content="{Binding .}">
<ContentControl.ContentTemplate>
<DataTemplate>
<Grid Background="#FFE8E8E8" HorizontalAlignment="Stretch" MinHeight="35">
<Grid.ColumnDefinitions>
<ColumnDefinition MinWidth="75"/>
<ColumnDefinition MinWidth="150"/>
<ColumnDefinition MinWidth="30"/>
</Grid.ColumnDefinitions>
<TextBlock Margin="3 1 1 1" Text="{Binding Name}" HorizontalAlignment="Left" VerticalAlignment="Center"/>
<TextBox Grid.Column="1" Margin="1" VerticalAlignment="Center" HorizontalAlignment="Stretch" />
<Label Grid.Column="2" Margin="1" VerticalAlignment="Center">
<CheckBox />
</Label>
</Grid>
</DataTemplate>
</ContentControl.ContentTemplate>
</ContentControl>
</Grid>
</HierarchicalDataTemplate>
</HierarchicalDataTemplate.ItemTemplate>
<ContentControl Content="{Binding .}">
<ContentControl.ContentTemplate>
<DataTemplate>
<Grid Background="#FFE8E8E8" HorizontalAlignment="Stretch" Width="255" MinHeight="35">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="75"/>
<ColumnDefinition Width="150"/>
<ColumnDefinition Width="30"/>
</Grid.ColumnDefinitions>
<TextBlock Margin="1" Text="{Binding Name}" HorizontalAlignment="Left" VerticalAlignment="Center"/>
<TextBox Grid.Column="1" Margin="1" VerticalAlignment="Center" HorizontalAlignment="Stretch" />
<Label Grid.Column="2" Margin="1" VerticalAlignment="Center">
<CheckBox />
</Label>
</Grid>
</DataTemplate>
</ContentControl.ContentTemplate>
</ContentControl>
</HierarchicalDataTemplate>
</myMenu:TreeViewFloatingDisplay.ItemTemplate>
</myMenu:TreeViewFloatingDisplay>
</Grid>
ViewModel.cs
public class ViewModel
{
public ObservableCollection<Country> Countries { get; set; }
public ViewModel()
{
Countries = new ObservableCollection<Country>();
Countries.Add(new Country()
{
Name = "India",
States = new ObservableCollection<State>()
{ new State()
{
Name="MP",
Cities = new ObservableCollection<City>()
{
new City(){Name = "Bhopal"},new City(){Name = "Indore"}, new City(){Name = "Ujjain"}
}
} ,
new State()
{
Name="UP",
Cities = new ObservableCollection<City>()
{
new City(){Name = "Agra"},new City(){Name = "Noida"}, new City(){Name = "Jhansi"}
}
} ,
new State()
{
Name="AP",
Cities = new ObservableCollection<City>()
{
new City(){Name = "Hyderabad"},new City(){Name = "Warangal"}, new City(){Name = "Vijaywada"}
}
}
}
});
Countries.Add(new Country()
{
Name = "Australia",
States = new ObservableCollection<State>()
{ new State()
{
Name="Tasmania",
Cities = new ObservableCollection<City>()
{
new City(){Name = "Sydney"},new City(){Name = "Melbourne"}
}
}
}
});
}
}
public class Country
{
public string Name { get; set; }
public ObservableCollection<State> States { get; set; }
}
public class State
{
public string Name { get; set; }
public ObservableCollection<City> Cities { get; set; }
}
public class City
{
public string Name { get; set; }
}
