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我有一个树视图表示,其中每个项目都有一个复选框的项目的层次结构。我想在树形视图下面显示一个包含所有选中项的列表框。如何使用MVVM模式实现这样的功能?WPF Treeview和列表框同步
在此先感谢 卢卡斯Glaz
我有一个树视图表示,其中每个项目都有一个复选框的项目的层次结构。我想在树形视图下面显示一个包含所有选中项的列表框。如何使用MVVM模式实现这样的功能?WPF Treeview和列表框同步
在此先感谢 卢卡斯Glaz
下面是一个例子:
视图模型
public class TreeNodeViewModel : ViewModelBase
{
#region Constructors
public TreeNodeViewModel(string text, params TreeNodeViewModel[] nodes)
: this(text, new ObservableCollection<TreeNodeViewModel>(nodes))
{
}
public TreeNodeViewModel(string text, ObservableCollection<TreeNodeViewModel> nodes)
{
Text = text;
Nodes = nodes;
foreach (var node in Nodes)
{
node.Parent = this;
}
Nodes.CollectionChanged += new System.Collections.Specialized.NotifyCollectionChangedEventHandler(Nodes_CollectionChanged);
}
#endregion
#region Private methods
private void Nodes_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
{
foreach (var node in e.OldItems.Cast<TreeNodeViewModel>())
{
node.Parent = null;
}
foreach (var node in e.NewItems.Cast<TreeNodeViewModel>())
{
node.Parent = this;
}
OnPropertyChanged("CheckedNodes");
}
private void NotifyParent()
{
if (Parent != null)
{
Parent.OnPropertyChanged("CheckedNodes");
Parent.NotifyParent();
}
}
#endregion
#region Private data
private string _text;
private bool _isChecked;
private TreeNodeViewModel _parent;
#endregion
#region Public properties
public string Text
{
get { return _text; }
set
{
if (value != _text)
{
_text = value;
OnPropertyChanged("Text");
}
}
}
public bool IsChecked
{
get { return _isChecked; }
set
{
if (value != _isChecked)
{
_isChecked = value;
NotifyParent();
OnPropertyChanged("IsChecked");
}
}
}
public ObservableCollection<TreeNodeViewModel> Nodes { get; private set; }
public IEnumerable<TreeNodeViewModel> CheckedNodes
{
get
{
foreach (var node in Nodes)
{
if (node.IsChecked)
yield return node;
foreach (var child in node.CheckedNodes)
{
yield return child;
}
}
}
}
public TreeNodeViewModel Parent
{
get { return _parent; }
private set
{
if (value != _parent)
{
_parent = value;
OnPropertyChanged("Parent");
}
}
}
#endregion
}
XAML
<TreeView Grid.Row="0" ItemsSource="{Binding Nodes}">
<TreeView.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding Nodes}">
<StackPanel Orientation="Horizontal">
<CheckBox IsChecked="{Binding IsChecked}" />
<TextBlock Text="{Binding Text}" />
</StackPanel>
</HierarchicalDataTemplate>
</TreeView.ItemTemplate>
</TreeView>
<ListBox Grid.Row="1" ItemsSource="{Binding CheckedNodes}">
<ListBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Text}" />
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
代码隐藏
this.DataContext = new TreeNodeViewModel(
null,
new TreeNodeViewModel(
"1",
new TreeNodeViewModel(
"1.1",
new TreeNodeViewModel("1.1.1"),
new TreeNodeViewModel("1.1.2")),
new TreeNodeViewModel("1.2")),
new TreeNodeViewModel(
"2",
new TreeNodeViewModel("2.1"),
new TreeNodeViewModel(
"2.2",
new TreeNodeViewModel("2.2.1"))));
请注意,这是一个相当幼稚的做法,很容易就会被提高...例如,检查节点的整个列表重新评估每一个节点被选中/取消的时候,这可能导致糟糕表现为一个大的TreeView
谢谢您的非常详细,容易理解的例子:) – GUZ 2009-10-13 12:56:17