38
内置的WPF TreeView控件不允许多选，就像ListBox一样。我如何定制TreeView以允许多重选择而不重写它。自定义TreeView以允许多选
A
回答
4
当我认为覆盖控件的基本行为，比如树视图时，我总是喜欢考虑与我的决定相关的可用性和努力。
在treeview的特定情况下，我发现切换到一个listview与零个，一个或多个控件的组合使得更易于实现的更有用的解决方案。
作为示例，请考虑常见的“打开”对话框或Windows资源管理器应用程序。
2
我已经简化了这项任务，在每个treeviewitem的文本前添加一个复选框。
所以，我创建了一个有2个项目的dockpanel：checkbox + textblock。
所以......
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
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);
然后你就可以访问复选框值：
void item_Selected(object sender, RoutedEventArgs e)
{
selectedTVI = ((TreeViewItem)sender);
CheckBox cb = (Checkbox)((DockPanel)selectedTVI.Header).Children[0];
}
如果你不需要任何复杂的东西，这是一个简单的方法。
1
我终于编写了我自己的包含TreeView的CustomControl里面。基于他人的功能键位于上制作树视图模型的所有项目继承接口ISelectable工作：
public interface ISelectable
{
public bool IsSelected {get; set}
}
这种方式，我们将有一个新的“IsSelected”属性，有什么可使用TreeViewItem IsSelected进行操作。我们只需要对我们的树进行样式设置，以便处理IsSelected属性的模型。下面的代码（它使用可在http://code.google.com/p/gong-wpf-dragdrop/拖动&降库）：
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＃：
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
}
}
2
我有SOMOS实施的变化使用在派生基类TreeView控件上声明的附加属性，以跟踪TreeViewItems的选择状态。这样可以保持TreeViewItem元素本身的选择跟踪，并且不会影响树视图呈现的模型对象。
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
}
}
这里是XAML。请注意，突出部分是使用MultiSelectTreeViewItemStyle中新增的“IsItemSelected”附加属性来替代使用单数“IsSelected”属性的两个触发器，以实现可视状态。
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>
这里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);
}
}
}
这里是MainWindow代码隐藏的按钮点击处理程序，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);
}
希望这会有所帮助。
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你可以看看[TreeViewEx]（http://treeviewex.codeplex.com/）的例子。 – 2012-02-15 16:26:04
另一个更直接解决您的问题的CodeProject项目是这样的： [WPF MultiSelect TreeView示例]（http://www.codeproject.com/KB/WPF/WPFMultiSelectTreeView.aspx）。 – Govert 2009-09-25 08:20:48
@Govert这篇文章中的代码写得很糟糕。我不会推荐给任何人。就好像作者比编码花费更多的时间来表达他的代码。 – 2010-03-26 13:51:55