在虚拟的WPF树视图中滚动是非常不稳定的

如果在TreeView中启用了具有不同大小的项目的虚拟化，则会出现多个问题:

• 垂直滚动条随机改变其大小，并且在查看整个树后不会记住元素的大小。

• 上下滚动后，ArgumentNullException从框架代码中抛出。

复制很简单:创建一个新的WPF应用程序，然后将此代码放入MainWindow.xaml

<Window x:Class="VirtualTreeView.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="800" Width="400" Left="0" Top="0"
        DataContext="{Binding RelativeSource={RelativeSource Self}}">
    <Grid>
        <TreeView x:Name="tvwItems" ItemsSource="{Binding Items}"
                VirtualizingPanel.IsVirtualizing="True" VirtualizingPanel.VirtualizationMode="Recycling">
            <TreeView.ItemTemplate>
                <DataTemplate>
                    <Border Height="{Binding Height}" Width="{Binding Height}"
                            BorderThickness="1" Background="DarkGray" BorderBrush="DarkBlue"/>
                </DataTemplate>
            </TreeView.ItemTemplate>
        </TreeView>
    </Grid>
</Window>

并将此代码放入MainWindow.xaml.cs

using System.Collections.ObjectModel;
using System.Linq;
namespace VirtualTreeView
{
    public partial class MainWindow
    {
        public ObservableCollection<Item> Items { get; set; }
        public MainWindow ()
        {
            Items = new ObservableCollection<Item>(Enumerable.Range(0, 20).Select(i => new Item {
                Height = i*20,
            }));
            InitializeComponent();
        }
    }
    public class Item
    {
        public double Height { get; set; }
    }
}

当应用程序运行时，将鼠标光标移动到树视图中，使用鼠标滚轮滚动到底部，然后滚动到顶部，然后再次开始向下滚动。在中间的某个地方会抛出以下异常:

System.ArgumentNullException was unhandled
  HResult=-2147467261
  Message=Value cannot be null.
Parameter name: element
  Source=PresentationCore
  ParamName=element
  StackTrace:
       at MS.Internal.Media.VisualTreeUtils.AsNonNullVisual(DependencyObject element, Visual& visual, Visual3D& visual3D)
       at System.Windows.Media.VisualTreeHelper.GetParent(DependencyObject reference)
       at System.Windows.Controls.VirtualizingStackPanel.FindScrollOffset(Visual v)
       at System.Windows.Controls.VirtualizingStackPanel.OnAnchorOperation(Boolean isAnchorOperationPending)
       at System.Windows.Controls.VirtualizingStackPanel.OnAnchorOperation()
       at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
       at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
       at System.Windows.Threading.DispatcherOperation.InvokeImpl()
       at System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext(Object state)
       at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Windows.Threading.DispatcherOperation.Invoke()
       at System.Windows.Threading.Dispatcher.ProcessQueue()
       at System.Windows.Threading.Dispatcher.WndProcHook(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
       at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
       at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
       at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
       at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
       at System.Windows.Threading.Dispatcher.LegacyInvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
       at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
       at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg)
       at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
       at System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame)
       at System.Windows.Threading.Dispatcher.Run()
       at System.Windows.Application.RunDispatcher(Object ignore)
       at System.Windows.Application.RunInternal(Window window)
       at System.Windows.Application.Run(Window window)
       at System.Windows.Application.Run()
       at VirtualTreeView.App.Main() in d:'Docs'Projects'_Try'VirtualTreeView'obj'Debug'App.g.cs:line 0
       at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()

您还可以看到异常不是唯一的问题。上下滚动时，滚动条的大小会不断变化。(同样的问题不会出现在ListBox中，不能预测大小，但在查看整个列表后记住总高度)

问题:如何使滚动条正常运行并摆脱异常?(我不介意链接到替代的TreeView控件或可能虚拟化面板支持这种情况)