我製作了一個具有多列的自定義TreeView。一切都運行良好,直到你在樹上有很多物品。定製樹視圖虛擬化
我試着通過做VirtualizingPanel.IsVirtualizing="True"
(如果你是< .NET 4.5,將會是VirtualizingStackPanel.IsVirtualizing
)來啓用虛擬化,但它不僅加速它,它實際上使加載時間變得更糟。
在一個正常的TreeView這個屬性做的伎倆,但我無法找到一個方法來得到它在我的自定義工作樹
TreeViewItem.cs
public class TreeListViewItem : TreeViewItem
{
protected override DependencyObject GetContainerForItemOverride()
{
return new TreeListViewItem();
}
protected override bool IsItemItsOwnContainerOverride(object item)
{
return item is TreeListViewItem;
}
}
TreeListView.cs
public class TreeListView : TreeView
{
public GridViewColumnCollection Columns { get; set; }
public TreeListView()
{
Columns = new GridViewColumnCollection();
}
protected override DependencyObject GetContainerForItemOverride()
{
return new TreeListViewItem();
}
protected override bool IsItemItsOwnContainerOverride(object item)
{
return item is TreeListViewItem;
}
}
Node.cs
public class Node
{
public string Data { get; set; }
public List<Node> Children { get; set; }
public Node(string data)
{
Data = data;
Children = new List<Node>();
}
}
ViewModel.cs
public class ViewModel
{
public ObservableCollection<Node> Nodes { get; private set; }
public ViewModel()
{
Nodes = new ObservableCollection<Node>();
Node parent = new Node("Parent");
for (int i = 0; i < 5000; i++)
parent.Children.Add(new Node(i.ToString()));
Nodes.Add(parent);
}
}
MainWindow.xaml
<Window x:Class="WPFTest.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:WPFTest"
Title="Test"
mc:Ignorable="d"
Width="200">
<Window.DataContext>
<local:ViewModel/>
</Window.DataContext>
<Window.Resources>
<Style TargetType="local:TreeListView">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="local:TreeListView">
<Border BorderBrush="{TemplateBinding BorderBrush}"
BorderThickness="{TemplateBinding BorderThickness}">
<ScrollViewer VerticalScrollBarVisibility="Disabled">
<DockPanel>
<GridViewHeaderRowPresenter Columns="{Binding Path=Columns, RelativeSource={RelativeSource TemplatedParent}}"
DockPanel.Dock="Top"/>
<ScrollViewer HorizontalScrollBarVisibility="Disabled"
VerticalScrollBarVisibility="Auto"
DockPanel.Dock="Bottom">
<ItemsPresenter/>
</ScrollViewer>
</DockPanel>
</ScrollViewer>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Style TargetType="local:TreeListViewItem">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="local:TreeListViewItem">
<StackPanel>
<Border Name="Bd"
Background="{TemplateBinding Background}"
BorderBrush="{TemplateBinding BorderBrush}"
BorderThickness="{TemplateBinding BorderThickness}"
Padding="{TemplateBinding Padding}">
<GridViewRowPresenter x:Name="PART_Header"
Content="{TemplateBinding Header}"
Columns="{Binding Path=Columns, RelativeSource={RelativeSource AncestorType={x:Type local:TreeListView}}}" >
</GridViewRowPresenter>
</Border>
<ItemsPresenter x:Name="ItemsHost" />
</StackPanel>
<ControlTemplate.Triggers>
<Trigger Property="IsExpanded" Value="false">
<Setter TargetName="ItemsHost" Property="Visibility" Value="Collapsed"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Window.Resources>
<Grid>
<local:TreeListView ItemsSource="{Binding Nodes}" VirtualizingPanel.IsVirtualizing="True">
<TreeView.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding Children}"/>
</TreeView.ItemTemplate>
<local:TreeListView.Columns>
<GridViewColumn Header="Test" Width="150">
<GridViewColumn.CellTemplate>
<DataTemplate>
<DockPanel>
<TextBlock Text="{Binding Data}"/>
</DockPanel>
</DataTemplate>
</GridViewColumn.CellTemplate>
</GridViewColumn>
</local:TreeListView.Columns>
</local:TreeListView>
</Grid>
</Window>
我想模板化的ItemPanel是VirtualizingStackPanel
並沒有幫助。
我去掉了擴展器部分,因爲它不相關。您可以雙擊父節點來展開樹,加載子節點需要很長時間。
永遠不會想到CanContentScroll可能會對此產生影響。拯救生命 – Steve