wpf 自定义 TreeView 以允许多选
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时间：2020-09-08 19:58:34 来源:igfitidea点击:
Customizing the TreeView to allow multi select
提问by Dylan
The built-in WPF TreeView control does not allow for multi selection, like a ListBox does. How can I customize the TreeView to allow for multi selection without rewriting it.
内置的 WPF TreeView 控件不允许多选，就像 ListBox 那样。如何自定义 TreeView 以允许多选而不重写它。
回答by Nishan Hossepian
I have a variation on SoMoS implementation that uses an attached property declared on a derivation of the base TreeView control to track the selection state of the TreeViewItems. This keeps the selection tracking on the TreeViewItem element itself, and off of the model object being presented by the tree-view.
我在 SoMoS 实现上有一个变体，它使用在基本 TreeView 控件的派生上声明的附加属性来跟踪 TreeViewItems 的选择状态。这将保持对 TreeViewItem 元素本身的选择跟踪，以及树视图呈现的模型对象。
This is the new TreeView class derivation.
这是新的 TreeView 类派生。
using System.Linq;
using System.Windows;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Shapes;
using System.Windows.Controls;
using System.Collections;
using System.Collections.Generic;
namespace MultiSelectTreeViewDemo
{
public sealed class MultiSelectTreeView : TreeView
{
#region Fields
// Used in shift selections
private TreeViewItem _lastItemSelected;
#endregion Fields
#region Dependency Properties
public static readonly DependencyProperty IsItemSelectedProperty =
DependencyProperty.RegisterAttached("IsItemSelected", typeof(bool), typeof(MultiSelectTreeView));
public static void SetIsItemSelected(UIElement element, bool value)
{
element.SetValue(IsItemSelectedProperty, value);
}
public static bool GetIsItemSelected(UIElement element)
{
return (bool)element.GetValue(IsItemSelectedProperty);
}
#endregion Dependency Properties
#region Properties
private static bool IsCtrlPressed
{
get { return Keyboard.IsKeyDown(Key.LeftCtrl) || Keyboard.IsKeyDown(Key.RightCtrl); }
}
private static bool IsShiftPressed
{
get { return Keyboard.IsKeyDown(Key.LeftShift) || Keyboard.IsKeyDown(Key.RightShift); }
}
public IList SelectedItems
{
get
{
var selectedTreeViewItems = GetTreeViewItems(this, true).Where(GetIsItemSelected);
var selectedModelItems = selectedTreeViewItems.Select(treeViewItem => treeViewItem.Header);
return selectedModelItems.ToList();
}
}
#endregion Properties
#region Event Handlers
protected override void OnPreviewMouseDown(MouseButtonEventArgs e)
{
base.OnPreviewMouseDown(e);
// If clicking on a tree branch expander...
if (e.OriginalSource is Shape || e.OriginalSource is Grid || e.OriginalSource is Border)
return;
var item = GetTreeViewItemClicked((FrameworkElement)e.OriginalSource);
if (item != null) SelectedItemChangedInternal(item);
}
#endregion Event Handlers
#region Utility Methods
private void SelectedItemChangedInternal(TreeViewItem tvItem)
{
// Clear all previous selected item states if ctrl is NOT being held down
if (!IsCtrlPressed)
{
var items = GetTreeViewItems(this, true);
foreach (var treeViewItem in items)
SetIsItemSelected(treeViewItem, false);
}
// Is this an item range selection?
if (IsShiftPressed && _lastItemSelected != null)
{
var items = GetTreeViewItemRange(_lastItemSelected, tvItem);
if (items.Count > 0)
{
foreach (var treeViewItem in items)
SetIsItemSelected(treeViewItem, true);
_lastItemSelected = items.Last();
}
}
// Otherwise, individual selection
else
{
SetIsItemSelected(tvItem, true);
_lastItemSelected = tvItem;
}
}
private static TreeViewItem GetTreeViewItemClicked(DependencyObject sender)
{
while (sender != null && !(sender is TreeViewItem))
sender = VisualTreeHelper.GetParent(sender);
return sender as TreeViewItem;
}
private static List<TreeViewItem> GetTreeViewItems(ItemsControl parentItem, bool includeCollapsedItems, List<TreeViewItem> itemList = null)
{
if (itemList == null)
itemList = new List<TreeViewItem>();
for (var index = 0; index < parentItem.Items.Count; index++)
{
var tvItem = parentItem.ItemContainerGenerator.ContainerFromIndex(index) as TreeViewItem;
if (tvItem == null) continue;
itemList.Add(tvItem);
if (includeCollapsedItems || tvItem.IsExpanded)
GetTreeViewItems(tvItem, includeCollapsedItems, itemList);
}
return itemList;
}
private List<TreeViewItem> GetTreeViewItemRange(TreeViewItem start, TreeViewItem end)
{
var items = GetTreeViewItems(this, false);
var startIndex = items.IndexOf(start);
var endIndex = items.IndexOf(end);
var rangeStart = startIndex > endIndex || startIndex == -1 ? endIndex : startIndex;
var rangeCount = startIndex > endIndex ? startIndex - endIndex + 1 : endIndex - startIndex + 1;
if (startIndex == -1 && endIndex == -1)
rangeCount = 0;
else if (startIndex == -1 || endIndex == -1)
rangeCount = 1;
return rangeCount > 0 ? items.GetRange(rangeStart, rangeCount) : new List<TreeViewItem>();
}
#endregion Utility Methods
}
}
And here's the XAML. Make note that the salient part is the replacement of the two triggers that use the singular 'IsSelected' property with the new 'IsItemSelected' attached property in the MultiSelectTreeViewItemStyle to achieve the visual state.
这是 XAML。请注意，突出的部分是在 MultiSelectTreeViewItemStyle 中使用新的 'IsItemSelected' 附加属性替换使用单数 'IsSelected' 属性的两个触发器，以实现视觉状态。
Also note I'm not aggregating the new TreeView control into a UserControl.
另请注意，我没有将新的 TreeView 控件聚合到 UserControl 中。
<Window
x:Class="MultiSelectTreeViewDemo.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:MultiSelectTreeViewDemo"
Title="MultiSelect TreeView Demo" Height="350" Width="525">
<Window.Resources>
<local:DemoViewModel x:Key="ViewModel"/>
<Style x:Key="TreeViewItemFocusVisual">
<Setter Property="Control.Template">
<Setter.Value>
<ControlTemplate>
<Rectangle/>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.Static.Checked.Fill" Color="#FF595959"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.Static.Checked.Stroke" Color="#FF262626"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.MouseOver.Stroke" Color="#FF1BBBFA"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.MouseOver.Fill" Color="Transparent"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.MouseOver.Checked.Stroke" Color="#FF262626"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.MouseOver.Checked.Fill" Color="#FF595959"/>
<PathGeometry x:Key="TreeArrow" Figures="M0,0 L0,6 L6,0 z"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.Static.Fill" Color="Transparent"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.Static.Stroke" Color="#FF989898"/>
<Style x:Key="ExpandCollapseToggleStyle" TargetType="{x:Type ToggleButton}">
<Setter Property="Focusable" Value="False"/>
<Setter Property="Width" Value="16"/>
<Setter Property="Height" Value="16"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ToggleButton}">
<Border Background="Transparent" Height="16" Padding="5,5,5,5" Width="16">
<Path x:Name="ExpandPath" Data="{StaticResource TreeArrow}" Fill="{StaticResource TreeViewItem.TreeArrow.Static.Fill}" Stroke="{StaticResource TreeViewItem.TreeArrow.Static.Stroke}">
<Path.RenderTransform>
<RotateTransform Angle="135" CenterY="3" CenterX="3"/>
</Path.RenderTransform>
</Path>
</Border>
<ControlTemplate.Triggers>
<Trigger Property="IsChecked" Value="True">
<Setter Property="RenderTransform" TargetName="ExpandPath">
<Setter.Value>
<RotateTransform Angle="180" CenterY="3" CenterX="3"/>
</Setter.Value>
</Setter>
<Setter Property="Fill" TargetName="ExpandPath" Value="{StaticResource TreeViewItem.TreeArrow.Static.Checked.Fill}"/>
<Setter Property="Stroke" TargetName="ExpandPath" Value="{StaticResource TreeViewItem.TreeArrow.Static.Checked.Stroke}"/>
</Trigger>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Stroke" TargetName="ExpandPath" Value="{StaticResource TreeViewItem.TreeArrow.MouseOver.Stroke}"/>
<Setter Property="Fill" TargetName="ExpandPath" Value="{StaticResource TreeViewItem.TreeArrow.MouseOver.Fill}"/>
</Trigger>
<MultiTrigger>
<MultiTrigger.Conditions>
<Condition Property="IsMouseOver" Value="True"/>
<Condition Property="IsChecked" Value="True"/>
</MultiTrigger.Conditions>
<Setter Property="Stroke" TargetName="ExpandPath" Value="{StaticResource TreeViewItem.TreeArrow.MouseOver.Checked.Stroke}"/>
<Setter Property="Fill" TargetName="ExpandPath" Value="{StaticResource TreeViewItem.TreeArrow.MouseOver.Checked.Fill}"/>
</MultiTrigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Style x:Key="MultiSelectTreeViewItemStyle" TargetType="{x:Type TreeViewItem}">
<Setter Property="Background" Value="Transparent"/>
<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="Padding" Value="1,0,0,0"/>
<Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>
<Setter Property="FocusVisualStyle" Value="{StaticResource TreeViewItemFocusVisual}"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type TreeViewItem}">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition MinWidth="19" Width="Auto"/>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition/>
</Grid.RowDefinitions>
<ToggleButton
x:Name="Expander"
ClickMode="Press"
IsChecked="{Binding IsExpanded, RelativeSource={RelativeSource TemplatedParent}}"
Style="{StaticResource ExpandCollapseToggleStyle}"/>
<Border
x:Name="Bd"
BorderBrush="{TemplateBinding BorderBrush}"
BorderThickness="{TemplateBinding BorderThickness}"
Background="{TemplateBinding Background}"
Grid.Column="1"
Padding="{TemplateBinding Padding}"
SnapsToDevicePixels="true">
<ContentPresenter
x:Name="PART_Header"
ContentSource="Header"
HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
</Border>
<ItemsPresenter
x:Name="ItemsHost"
Grid.ColumnSpan="2"
Grid.Column="1"
Grid.Row="1"/>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="IsExpanded" Value="false">
<Setter Property="Visibility" TargetName="ItemsHost" Value="Collapsed"/>
</Trigger>
<Trigger Property="HasItems" Value="false">
<Setter Property="Visibility" TargetName="Expander" Value="Hidden"/>
</Trigger>
<!--Trigger Property="IsSelected" Value="true"-->
<Trigger Property="local:MultiSelectTreeView.IsItemSelected" Value="true">
<Setter Property="Background" TargetName="Bd" Value="{DynamicResource {x:Static SystemColors.HighlightBrushKey}}"/>
<Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.HighlightTextBrushKey}}"/>
</Trigger>
<MultiTrigger>
<MultiTrigger.Conditions>
<!--Condition Property="IsSelected" Value="true"/-->
<Condition Property="local:MultiSelectTreeView.IsItemSelected" Value="true"/>
<Condition Property="IsSelectionActive" Value="false"/>
</MultiTrigger.Conditions>
<Setter Property="Background" TargetName="Bd" Value="{DynamicResource {x:Static SystemColors.InactiveSelectionHighlightBrushKey}}"/>
<Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.InactiveSelectionHighlightTextBrushKey}}"/>
</MultiTrigger>
<Trigger Property="IsEnabled" Value="false">
<Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
<Style.Triggers>
<Trigger Property="VirtualizingPanel.IsVirtualizing" Value="true">
<Setter Property="ItemsPanel">
<Setter.Value>
<ItemsPanelTemplate>
<VirtualizingStackPanel/>
</ItemsPanelTemplate>
</Setter.Value>
</Setter>
</Trigger>
</Style.Triggers>
</Style>
</Window.Resources>
<Grid
Background="WhiteSmoke"
DataContext="{DynamicResource ViewModel}">
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<local:MultiSelectTreeView
x:Name="multiSelectTreeView"
ItemContainerStyle="{StaticResource MultiSelectTreeViewItemStyle}"
ItemsSource="{Binding FoodGroups}">
<local:MultiSelectTreeView.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding Children}">
<Grid>
<TextBlock FontSize="14" Text="{Binding Name}"/>
</Grid>
</HierarchicalDataTemplate>
</local:MultiSelectTreeView.ItemTemplate>
</local:MultiSelectTreeView>
<Button
Grid.Row="1"
Margin="0,10"
Padding="20,2"
HorizontalAlignment="Center"
Content="Get Selections"
Click="GetSelectionsButton_OnClick"/>
</Grid>
</Window>
And here's a cheesy view-model to drive it (for demo purposes).
这是一个俗气的视图模型来驱动它（用于演示目的）。
using System.Collections.ObjectModel;
namespace MultiSelectTreeViewDemo
{
public sealed class DemoViewModel
{
public ObservableCollection<FoodItem> FoodGroups { get; set; }
public DemoViewModel()
{
var redMeat = new FoodItem { Name = "Reds" };
redMeat.Add(new FoodItem { Name = "Beef" });
redMeat.Add(new FoodItem { Name = "Buffalo" });
redMeat.Add(new FoodItem { Name = "Lamb" });
var whiteMeat = new FoodItem { Name = "Whites" };
whiteMeat.Add(new FoodItem { Name = "Chicken" });
whiteMeat.Add(new FoodItem { Name = "Duck" });
whiteMeat.Add(new FoodItem { Name = "Pork" });
var meats = new FoodItem { Name = "Meats", Children = { redMeat, whiteMeat } };
var veggies = new FoodItem { Name = "Vegetables" };
veggies.Add(new FoodItem { Name = "Potato" });
veggies.Add(new FoodItem { Name = "Corn" });
veggies.Add(new FoodItem { Name = "Spinach" });
var fruits = new FoodItem { Name = "Fruits" };
fruits.Add(new FoodItem { Name = "Apple" });
fruits.Add(new FoodItem { Name = "Orange" });
fruits.Add(new FoodItem { Name = "Pear" });
FoodGroups = new ObservableCollection<FoodItem> { meats, veggies, fruits };
}
}
public sealed class FoodItem
{
public string Name { get; set; }
public ObservableCollection<FoodItem> Children { get; set; }
public FoodItem()
{
Children = new ObservableCollection<FoodItem>();
}
public void Add(FoodItem item)
{
Children.Add(item);
}
}
}
And here's the button click-handler on the MainWindow code-behind that shows the selections in a MessageBox.
这是 MainWindow 代码隐藏上的按钮单击处理程序，它显示了 MessageBox 中的选择。
private void GetSelectionsButton_OnClick(object sender, RoutedEventArgs e)
{
var selectedMesg = "";
var selectedItems = multiSelectTreeView.SelectedItems;
if (selectedItems.Count > 0)
{
selectedMesg = selectedItems.Cast<FoodItem>()
.Where(modelItem => modelItem != null)
.Aggregate(selectedMesg, (current, modelItem) => current + modelItem.Name + Environment.NewLine);
}
else
selectedMesg = "No selected items!";
MessageBox.Show(selectedMesg, "MultiSelect TreeView Demo", MessageBoxButton.OK);
}
Hope this helps.
希望这可以帮助。
回答by Zamboni
When I consider overriding the fundamental behavior of a control, like a treeview, I always like to consider the usability and effort associated with my decision.
当我考虑覆盖控件的基本行为时，如树视图，我总是喜欢考虑与我的决定相关的可用性和工作量。
In the specific case of a treeview I find that switching to a listview in combination with zero, one, or more controls makes for a more usable solution that often is easier to implement.
在树视图的特定情况下，我发现切换到列表视图并结合零个、一个或多个控件可以形成更易于实现的更有用的解决方案。
As an example, consider the common Open dialog, or Windows Explorer application.
例如，考虑常见的打开对话框或 Windows 资源管理器应用程序。
回答by Web Developer
I've simplified this task adding a checkbox before the text for each treeviewitem.
我简化了这个任务，在每个 treeviewitem 的文本之前添加了一个复选框。
So, I've created a dockpanel with 2 items inside: checkbox + textblock.
因此，我创建了一个包含 2 个项目的停靠面板：复选框 + 文本块。
So...
所以...
XAML
XAML
<TreeView x:Name="treeViewProcesso" Margin="1,30.351,1,5" BorderBrush="{x:Null}" MinHeight="250" VerticalContentAlignment="Top" BorderThickness="0" >
<TreeViewItem Header="Documents" x:Name="treeView" IsExpanded="True" DisplayMemberPath="DocumentsId" >
</TreeViewItem>
</TreeView>
CS
CS
TreeViewItem treeViewItem = new TreeViewItem();
DockPanel dp = new DockPanel();
CheckBox cb = new CheckBox();
TextBlock tb = new TextBlock();
tb.Text = "Item";
dp.Children.Add(cb);
dp.Children.Add(tb);
treeViewItem.Header = dp;
treeViewItem.Selected += new RoutedEventHandler(item_Selected);
treeView.Items.Add(treeViewItem);
And then you can access checkbox value:
然后您可以访问复选框值：
void item_Selected(object sender, RoutedEventArgs e)
{
selectedTVI = ((TreeViewItem)sender);
CheckBox cb = (Checkbox)((DockPanel)selectedTVI.Header).Children[0];
}
This is a simple way to do if you don't need anything complex.
如果您不需要任何复杂的东西，这是一种简单的方法。
回答by Ignacio Soler Garcia
I finally ended coding my own CustomControl containing a TreeView inside. Based on the work of others the key of the functionality resides on making all the items of the Model of the TreeView inherit the interface ISelectable:
我终于结束了我自己的包含 TreeView 的 CustomControl 的编码。基于其他人的工作，功能的关键在于使 TreeView 的 Model 的所有项都继承接口 ISelectable：
public interface ISelectable
{
public bool IsSelected {get; set}
}
This way we will have a new 'IsSelected' property that has nothing to do with the TreeViewItem IsSelected. We just need to style our tree so it handles the model IsSelected property. Here the code (it's using the Drag & drop libraries available at http://code.google.com/p/gong-wpf-dragdrop/):
这样我们将有一个新的“IsSelected”属性，它与 TreeViewItem IsSelected 无关。我们只需要为我们的树设置样式，以便它处理模型 IsSelected 属性。这里的代码（它使用http://code.google.com/p/gong-wpf-dragdrop/ 上提供的拖放库）：
XAML
XAML
<UserControl x:Class="Picis.Wpf.Framework.ExtendedControls.TreeViewEx.TreeViewEx"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:DragAndDrop="clr-namespace:Picis.Wpf.Framework.DragAndDrop">
<TreeView ItemsSource="{Binding ItemsSource, RelativeSource={RelativeSource AncestorType=UserControl}}"
ItemTemplate="{Binding ItemTemplate, RelativeSource={RelativeSource AncestorType=UserControl}}"
ItemContainerStyle="{Binding ItemContainerStyle, RelativeSource={RelativeSource AncestorType=UserControl}}"
DragAndDrop:DragDrop.DropHandler ="{Binding DropHandler, RelativeSource={RelativeSource AncestorType=UserControl}}"
PreviewMouseDown="TreeViewOnPreviewMouseDown"
PreviewMouseUp="TreeViewOnPreviewMouseUp"
x:FieldModifier="private" x:Name="InnerTreeView" >
<TreeView.Resources>
<Style TargetType="TreeViewItem">
<Style.Resources>
<SolidColorBrush x:Key="{x:Static SystemColors.HighlightBrushKey}" Color="White" />
<SolidColorBrush x:Key="{x:Static SystemColors.HighlightTextBrushKey}" Color="Black" />
<SolidColorBrush x:Key="{x:Static SystemColors.ControlBrushKey}" Color="White" />
</Style.Resources>
</Style>
</TreeView.Resources>
</TreeView>
C#:
C＃：
using System.Collections.Generic;
using System.Linq;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Shapes;
using GongSolutions.Wpf.DragDrop;
using DragDrop = GongSolutions.Wpf.DragDrop;
namespace <yournamespace>.TreeViewEx
{
public partial class TreeViewEx : UserControl
{
#region Attributes
private TreeViewItem _lastItemSelected; // Used in shift selections
private TreeViewItem _itemToCheck; // Used when clicking on a selected item to check if we want to deselect it or to drag the current selection
private bool _isDragEnabled;
private bool _isDropEnabled;
#endregion
#region Dependency Properties
public static readonly DependencyProperty ItemsSourceProperty = DependencyProperty.Register("ItemsSource", typeof(IEnumerable<ISelectable>), typeof(TreeViewEx));
public IEnumerable<ISelectable> ItemsSource
{
get
{
return (IEnumerable<ISelectable>)this.GetValue(TreeViewEx.ItemsSourceProperty);
}
set
{
this.SetValue(TreeViewEx.ItemsSourceProperty, value);
}
}
public static readonly DependencyProperty ItemTemplateProperty = DependencyProperty.Register("ItemTemplate", typeof(DataTemplate), typeof(TreeViewEx));
public DataTemplate ItemTemplate
{
get
{
return (DataTemplate)GetValue(TreeViewEx.ItemTemplateProperty);
}
set
{
SetValue(TreeViewEx.ItemTemplateProperty, value);
}
}
public static readonly DependencyProperty ItemContainerStyleProperty = DependencyProperty.Register("ItemContainerStyle", typeof(Style), typeof(TreeViewEx));
public Style ItemContainerStyle
{
get
{
return (Style)GetValue(TreeViewEx.ItemContainerStyleProperty);
}
set
{
SetValue(TreeViewEx.ItemContainerStyleProperty, value);
}
}
public static readonly DependencyProperty DropHandlerProperty = DependencyProperty.Register("DropHandler", typeof(IDropTarget), typeof(TreeViewEx));
public IDropTarget DropHandler
{
get
{
return (IDropTarget)GetValue(TreeViewEx.DropHandlerProperty);
}
set
{
SetValue(TreeViewEx.DropHandlerProperty, value);
}
}
#endregion
#region Properties
public bool IsDragEnabled
{
get
{
return _isDragEnabled;
}
set
{
if (_isDragEnabled != value)
{
_isDragEnabled = value;
DragDrop.SetIsDragSource(this.InnerTreeView, _isDragEnabled);
}
}
}
public bool IsDropEnabled
{
get
{
return _isDropEnabled;
}
set
{
if (_isDropEnabled != value)
{
_isDropEnabled = value;
DragDrop.SetIsDropTarget(this.InnerTreeView, _isDropEnabled);
}
}
}
#endregion
#region Public Methods
public TreeViewEx()
{
InitializeComponent();
}
#endregion
#region Event Handlers
private void TreeViewOnPreviewMouseDown(object sender, MouseButtonEventArgs e)
{
if (e.OriginalSource is Shape || e.OriginalSource is Grid || e.OriginalSource is Border) // If clicking on the + of the tree
return;
TreeViewItem item = this.GetTreeViewItemClicked((FrameworkElement)e.OriginalSource);
if (item != null && item.Header != null)
{
this.SelectedItemChangedHandler(item);
}
}
// Check done to avoid deselecting everything when clicking to drag
private void TreeViewOnPreviewMouseUp(object sender, MouseButtonEventArgs e)
{
if (_itemToCheck != null)
{
TreeViewItem item = this.GetTreeViewItemClicked((FrameworkElement)e.OriginalSource);
if (item != null && item.Header != null)
{
if (!TreeViewEx.IsCtrlPressed)
{
GetTreeViewItems(true).Select(t => t.Header).Cast<ISelectable>().ToList().ForEach(f => f.IsSelected = false);
((ISelectable)_itemToCheck.Header).IsSelected = true;
_lastItemSelected = _itemToCheck;
}
else
{
((ISelectable)_itemToCheck.Header).IsSelected = false;
_lastItemSelected = null;
}
}
}
}
#endregion
#region Private Methods
private void SelectedItemChangedHandler(TreeViewItem item)
{
ISelectable content = (ISelectable)item.Header;
_itemToCheck = null;
if (content.IsSelected)
{
// Check it at the mouse up event to avoid deselecting everything when clicking to drag
_itemToCheck = item;
}
else
{
if (!TreeViewEx.IsCtrlPressed)
{
GetTreeViewItems(true).Select(t => t.Header).Cast<ISelectable>().ToList().ForEach(f => f.IsSelected = false);
}
if (TreeViewEx.IsShiftPressed && _lastItemSelected != null)
{
foreach (TreeViewItem tempItem in GetTreeViewItemsBetween(_lastItemSelected, item))
{
((ISelectable)tempItem.Header).IsSelected = true;
_lastItemSelected = tempItem;
}
}
else
{
content.IsSelected = true;
_lastItemSelected = item;
}
}
}
private static bool IsCtrlPressed
{
get
{
return Keyboard.IsKeyDown(Key.LeftCtrl) || Keyboard.IsKeyDown(Key.RightCtrl);
}
}
private static bool IsShiftPressed
{
get
{
return Keyboard.IsKeyDown(Key.LeftShift) || Keyboard.IsKeyDown(Key.RightShift);
}
}
private TreeViewItem GetTreeViewItemClicked(UIElement sender)
{
Point point = sender.TranslatePoint(new Point(0, 0), this.InnerTreeView);
DependencyObject visualItem = this.InnerTreeView.InputHitTest(point) as DependencyObject;
while (visualItem != null && !(visualItem is TreeViewItem))
{
visualItem = VisualTreeHelper.GetParent(visualItem);
}
return visualItem as TreeViewItem;
}
private IEnumerable<TreeViewItem> GetTreeViewItemsBetween(TreeViewItem start, TreeViewItem end)
{
List<TreeViewItem> items = this.GetTreeViewItems(false);
int startIndex = items.IndexOf(start);
int endIndex = items.IndexOf(end);
// It's possible that the start element has been removed after it was selected,
// I don't find a way to happen on the end but I add the code to handle the situation just in case
if (startIndex == -1 && endIndex == -1)
{
return new List<TreeViewItem>();
}
else if (startIndex == -1)
{
return new List<TreeViewItem>() {end};
}
else if (endIndex == -1)
{
return new List<TreeViewItem>() { start };
}
else
{
return startIndex > endIndex ? items.GetRange(endIndex, startIndex - endIndex + 1) : items.GetRange(startIndex, endIndex - startIndex + 1);
}
}
private List<TreeViewItem> GetTreeViewItems(bool includeCollapsedItems)
{
List<TreeViewItem> returnItems = new List<TreeViewItem>();
for (int index = 0; index < this.InnerTreeView.Items.Count; index++)
{
TreeViewItem item = (TreeViewItem)this.InnerTreeView.ItemContainerGenerator.ContainerFromIndex(index);
returnItems.Add(item);
if (includeCollapsedItems || item.IsExpanded)
{
returnItems.AddRange(GetTreeViewItemItems(item, includeCollapsedItems));
}
}
return returnItems;
}
private static IEnumerable<TreeViewItem> GetTreeViewItemItems(TreeViewItem treeViewItem, bool includeCollapsedItems)
{
List<TreeViewItem> returnItems = new List<TreeViewItem>();
for (int index = 0; index < treeViewItem.Items.Count; index++)
{
TreeViewItem item = (TreeViewItem)treeViewItem.ItemContainerGenerator.ContainerFromIndex(index);
if (item != null)
{
returnItems.Add(item);
if (includeCollapsedItems || item.IsExpanded)
{
returnItems.AddRange(GetTreeViewItemItems(item, includeCollapsedItems));
}
}
}
return returnItems;
}
#endregion
}
}
