我正在尝试UIElement
从 anInlineUIContainer
中正确删除 a 以便在另一个面板中使用它,但程序不断崩溃,并显示此消息“指定的视觉对象已经是另一个视觉对象的子对象或 CompositionTarget 的根。”。
我创建了一个小应用程序来说明我的痛苦。在这个程序中,一旦 Randy 按钮被他的女朋友杀死\删除,他仍然没有脱离他的父母,我发现他是UIElementIsland
. 然后任何尝试将 Randy 添加为其他任何东西的孩子都会使应用程序崩溃(天启按钮证明了我的观点 :))。您可以在删除 Randy 之前/之后单击查看 Randy 的父母,以注意到他UIElementIsland
小时候一直处于以下状态,如果他是分离的,整个问题\应该避免天启。
这是一个有趣的应用程序,所以即使只是为了好玩也可以复制和编译!任何帮助\想法将不胜感激!
C#部分:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Windows.Threading;
namespace DetachingfromUIElementIsland
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
int t = 0;
static string[] info = new string[] { "Okay, Lets have a look...", "Checking."
, "Checking..", "Checking...", "Seen it!" };
/// <summary>
/// Makes the App fancy :)
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
void timer_Tick(object sender, EventArgs e)
{
display.Text = info[t];
if (t == 0)
timer.Interval = new TimeSpan(0, 0, 0, 0, 300);
t++;
if (t >= 4)
{
t = 0;
timer.Stop();
display.Text = GetRandysParent();
}
}
private void deleteRandy_Click(object sender, RoutedEventArgs e)
{
// This might be the bug.
// Maybe there's a better way to do this.
// If there was a VisualTreeHelper.Remove().
randy_container.Child = null;
display.Text = "Haha! I just killed Randy!!! He'll never get the chance"
+ "\n to hurt another woman again!";
display.Background = Brushes.Violet;
end.Visibility = System.Windows.Visibility.Visible;
}
DispatcherTimer timer = null;
/// <summary>
/// Check if Randy is Still attached to UIElementIsland
/// </summary>
/// <returns></returns>
private string GetRandysParent()
{
// Check the visual tree to see if randy is removed properly
DependencyObject dp = VisualTreeHelper.GetParent(randy);
string text = string.Empty;
if (dp != null)
{
display.Background = Brushes.LightGreen;
text = "Randy's Dad is Mr " + dp.ToString();
}
else
{
// This should be what you'll get when the code works properly
display.Background = Brushes.Red;
text = "Weird...Randy doesn't seem to have a dad...";
}
return text;
}
private void findParents_Click(object sender, RoutedEventArgs e)
{
display.Background = Brushes.Yellow;
// Creates a timer to display some fancy stuff
// and then Randy's.
// Just to prove to you that this button actually works.
timer = new DispatcherTimer();
timer.Start();
timer.Tick += timer_Tick;
timer.Interval = new TimeSpan(0, 0, 0, 0, 700);
}
private void randy_Click(object sender, RoutedEventArgs e)
{
// Get Randy to introduce himself
display.Text = "Hi, I'm Randy!!!";
display.Background = Brushes.Orange;
}
private void end_Click(object sender, RoutedEventArgs e)
{
// If randy is removed properly, this would not crash the application.
StackPanel s = new StackPanel();
s.Children.Add(randy);
// CRASH!!!
}
}
}
XAML:
<Window x:Class="DetachingfromUIElementIsland.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525">
<FlowDocument IsEnabled="True" x:Name="document">
<Paragraph>
<InlineUIContainer x:Name="randy_container">
<!--Meet Randy-->
<Button Name="randy" Content="I am a Randy, the button" Click="randy_Click" ToolTip="Meet Randy"/>
</InlineUIContainer>
<LineBreak/>
<LineBreak/>
<InlineUIContainer x:Name="container2">
<!--Meet Randy's Ex Girlfriend-->
<Button Name="deleteRandy" Content="Randy dumped me for another girl :(, click me to delete him" Click="deleteRandy_Click" ToolTip="Meet Randy's Ex Girlfriend"/>
</InlineUIContainer>
<LineBreak/>
<LineBreak/>
<InlineUIContainer x:Name="container3">
<!--He can help you find Randy's Parents-->
<Button Name="findParents" Content="Click me to find randy's parents" Click="findParents_Click" ToolTip="He can help you find Randy's Parents"/>
</InlineUIContainer>
<LineBreak/>
<LineBreak/>
<InlineUIContainer x:Name="Apocalypse">
<!--End the world, Crash the application-->
<Button x:Name="end" Content="Avenge Randy's Death" Click="end_Click" ToolTip="End the world, Crash the application" Visibility="Hidden"/>
</InlineUIContainer>
</Paragraph>
<Paragraph>
<InlineUIContainer>
<TextBlock x:Name="display" Foreground="Black"/>
</InlineUIContainer>
</Paragraph>
</FlowDocument>
</Window>
整个代码应该比这更短,但我对其进行了调味以使其有点有趣。希望我能照亮某人的一天。但是,请帮助我:)。
答案:
从 Randy's 派生InlineUIContainer
如下:
public class DerivedInlineUIContainer : InlineUIContainer
{
public DerivedInlineUIContainer()
{
}
public void RemoveFromLogicalTree(FrameworkElement f)
{
this.RemoveLogicalChild(f);
}
}
现在你可以正确地杀死 Randy,并将他添加到 UIElement 天堂(The StackPanel
):
randy_container.RemoveFromLogicalTree(randy);
IDisposable disp = VisualTreeHelper.GetParent(randy) as IDisposable;
if (disp != null)
disp.Dispose();
// Poor Randy is going to heaven...
StackPanel heaven = new StackPanel();
heaven.add(randy);
谢谢大家。