wpf 指定的元素已经是另一个元素的逻辑子元素。先断开连接”

Question

提问by Antwan

i have user control that contain grid and inside it there is expander the problem is when i try to open new window that uses this user control i get an exception " Specified element is already the logical child of another element. Disconnect it first"
here is my code and its work when first windows created and the exception occur when show the second window

我有包含网格的用户控件，其中有扩展器问题是当我尝试打开使用此用户控件的新窗口时出现异常“指定的元素已经是另一个元素的逻辑子元素。首先断开它”
这里是我的代码及其在创建第一个窗口时的工作以及显示第二个窗口时发生的异常

 <UserControl x:Class="DiagramDesigner.WindowsUserControl"
                     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
                     xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
                     xmlns:s="clr-namespace:DiagramDesigner"
                xmlns:c="clr-namespace:DiagramDesigner.Controls"
                     mc:Ignorable="d" 

                     d:DesignHeight="700" d:DesignWidth="1000">
            <UserControl.Resources>
                <ContextMenu x:Key="DesignerCanvasContextMenu">
                    <MenuItem Header="Paste" Command="{x:Static ApplicationCommands.Paste}">
                        <MenuItem.Icon>
                            <Image Source="Resources/Images/Paste.png" Width="16"/>
                        </MenuItem.Icon>
                    </MenuItem>
                    <MenuItem Header="Select All" Command="{x:Static s:DesignerCanvas.SelectAll}"/>
                </ContextMenu>
            </UserControl.Resources>

            <Grid Margin="10">
                <Grid.RowDefinitions>

                    <RowDefinition Height="*"/>
                </Grid.RowDefinitions>


                <Grid Grid.Row="1" Margin="0,10,0,0">
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="200"/>
                        <ColumnDefinition/>
                    </Grid.ColumnDefinitions>
                    <!-- Toolbox -->
                    <StackPanel Grid.Column="0" Margin="0,0,5,0">
                        <Expander Header="Flow Chart" Content="{StaticResource FlowChartStencils}" IsExpanded="True" />
                    </StackPanel>
                    <!-- GridSplitter -->
                    <GridSplitter Focusable="False" Width="2" Background="LightGray"
                            VerticalAlignment="Stretch" HorizontalAlignment="Right"/>
                    <!-- Designer -->
                    <GroupBox Header="Diagram" Grid.Column="1" Margin="3,0,0,0">
                        <ScrollViewer HorizontalScrollBarVisibility="Auto"
                              VerticalScrollBarVisibility="Auto">
                            <s:DesignerCanvas Focusable="true" x:Name="MyDesigner"
                                    Background="{StaticResource WindowBackgroundBrush}"
                                    Margin="10" FocusVisualStyle="{x:Null}"
                                    ContextMenu="{StaticResource DesignerCanvasContextMenu}"/>
                        </ScrollViewer>
                    </GroupBox>
                </Grid>
            </Grid>
       </UserControl>

Answer 1

采纳答案by atomaras

You cannot reuse the same UIElement instance for different parts of the UI. Either remove it from the first and add it to the second one (not recommended but there are some advanced scenarios were it makes sense) or simply create a new one. It's pretty cheap.

不能为 UI 的不同部分重用相同的 UIElement 实例。要么将其从第一个中删除并将其添加到第二个中（不推荐，但有一些高级场景是有意义的）或简单地创建一个新场景。它很便宜。

Answer 2

回答by Contango

I had this error, and I managed to work out exactly why it was occurring using trial and error.

我遇到了这个错误，我设法通过反复试验找出了它发生的确切原因。

The problem? I was using the following line of XAML in bothcontext menus for a master/detail grid, using the DXGridfrom DevExpress.

问题？我在主/细节网格的两个上下文菜单中使用以下 XAML 行，使用DXGridfrom DevExpress.

<dxb:BarItemLinkSeparator />

Once I the issue was fixed, I noticed that the stack trace did actually give a small clue as to which XAML element was causing the error. The 4th line in the stack trace ends with this:

一旦我解决了问题，我注意到堆栈跟踪实际上确实提供了一个关于哪个 XAML 元素导致错误的小线索。堆栈跟踪中的第 4 行以这样结束：

[snip]ILinksHolder.OnLinkAdded(BarItemLinkBase link)

BarItemLinkBaseis the base class for BarItemLinkSeparator, which is our clue that removing said XAML will fix the error.

BarItemLinkBase是的基类BarItemLinkSeparator，这是我们删除所述 XAML 将修复错误的线索。

For context, here is the full stack trace:

对于上下文，这里是完整的堆栈跟踪：

System.InvalidOperationException: Specified element is already the logical child of another element. Disconnect it first.
  at System.Windows.FrameworkContentElement.ChangeLogicalParent(DependencyObject newParent)
  at System.Windows.FrameworkElement.AddLogicalChild(Object child)
  at DevExpress.Xpf.Bars.PopupMenu.DevExpress.Xpf.Bars.ILinksHolder.OnLinkAdded(BarItemLinkBase link)
  at DevExpress.Xpf.Bars.BarItemLinkCollection.UpdateItemLinkOnAddToCollection(BarItemLinkBase itemLink)
  at DevExpress.Xpf.Bars.BarItemLinkCollection.InsertItem(Int32 index, BarItemLinkBase itemLink)
  at DevExpress.Xpf.Bars.CustomizablePopupMenuBase.CustomizablePopupMenuItemLinkCollection.InsertItem(Int32 index, BarItemLinkBase itemLink)
  at System.Collections.ObjectModel.Collection`1.Add(T item)
  at DevExpress.Xpf.Bars.BarItemLinkBase.DevExpress.Xpf.Bars.IBarManagerControllerAction.Execute()
  at DevExpress.Xpf.Bars.BarManagerActionCollection.Execute()
  at DevExpress.Xpf.Bars.BarManagerActionContainer.Execute()
  at DevExpress.Xpf.Bars.BarManagerController.Execute()
  at DevExpress.Xpf.Bars.BarManagerMenuController.Execute()
  at DevExpress.Xpf.Grid.DataControlPopupMenu.ExecuteOriginationViewMenuController(Func`2 getMenuController)
  at DevExpress.Xpf.Grid.GridCellMenuInfo.ExecuteMenuController()
  at DevExpress.Xpf.Bars.CustomizablePopupMenuBase.CreateItems()
  at DevExpress.Xpf.Bars.CustomizablePopupMenuBase.RaiseOpening()
  at DevExpress.Xpf.Bars.BarPopupBase.OnIsOpenCoerce(Object value)
  at DevExpress.Xpf.Bars.PopupMenuBase.OnIsOpenCoerce(Object value)
  at DevExpress.Xpf.Bars.CustomizablePopupMenuBase.OnIsOpenCoerce(Object value)
  at DevExpress.Xpf.Bars.BarPopupBase.OnIsOpenCoerce(DependencyObject d, Object value)
  at System.Windows.DependencyObject.ProcessCoerceValue(DependencyProperty dp, PropertyMetadata metadata, EntryIndex& entryIndex, Int32& targetIndex, EffectiveValueEntry& newEntry, EffectiveValueEntry& oldEntry, Object& oldValue, Object baseValue, Object controlValue, CoerceValueCallback coerceValueCallback, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, Boolean skipBaseValueChecks)
  at System.Windows.DependencyObject.UpdateEffectiveValue(EntryIndex entryIndex, DependencyProperty dp, PropertyMetadata metadata, EffectiveValueEntry oldEntry, EffectiveValueEntry& newEntry, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType)
  at System.Windows.DependencyObject.SetValueCommon(DependencyProperty dp, Object value, PropertyMetadata metadata, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType, Boolean isInternal)
  at System.Windows.DependencyObject.SetValue(DependencyProperty dp, Object value)
  at System.Windows.Controls.Primitives.Popup.set_IsOpen(Boolean value)
  at DevExpress.Xpf.Bars.ContextMenuManager.ShowElementContextMenu(Object contextElement, Boolean openingFromKeyboard)
  at DevExpress.Xpf.Bars.ContextMenuManager.OpenContextMenu(Object sender, Boolean openingFromKeyboard)
  at DevExpress.Xpf.Bars.ContextMenuManager.OnContextMenuOpening(Object sender, ContextMenuEventArgs e)
  at System.Windows.Controls.ContextMenuEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)
  at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
  at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
  at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
  at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
  at System.Windows.UIElement.RaiseTrustedEvent(RoutedEventArgs args)
  at System.Windows.UIElement.RaiseEvent(RoutedEventArgs args, Boolean trusted)
  at System.Windows.Controls.PopupControlService.RaiseContextMenuOpeningEvent(IInputElement source, Double x, Double y, Boolean userInitiated)
  at System.Windows.Controls.PopupControlService.ProcessMouseUp(Object sender, MouseButtonEventArgs e)
  at System.Windows.Controls.PopupControlService.OnPostProcessInput(Object sender, ProcessInputEventArgs e)
  at System.Windows.Input.InputManager.RaiseProcessInputEventHandlers(ProcessInputEventHandler postProcessInput, ProcessInputEventArgs processInputEventArgs)
  at System.Windows.Input.InputManager.ProcessStagingArea()
  at System.Windows.Input.InputManager.ProcessInput(InputEventArgs input)
  at System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport)
  at System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawMouseActions actions, Int32 x, Int32 y, Int32 wheel)
  at System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr hwnd, WindowMessage msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
  at System.Windows.Interop.HwndSource.InputFilterMessage(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)


  System.InvalidOperationException: Specified element is already the logical child of another element. Disconnect it first.
     at System.Windows.FrameworkContentElement.ChangeLogicalParent(DependencyObject newParent)
     at System.Windows.FrameworkElement.AddLogicalChild(Object child)
     at DevExpress.Xpf.Bars.PopupMenu.DevExpress.Xpf.Bars.ILinksHolder.OnLinkAdded(BarItemLinkBase link)
     at DevExpress.Xpf.Bars.BarItemLinkCollection.UpdateItemLinkOnAddToCollection(BarItemLinkBase itemLink)
     at DevExpress.Xpf.Bars.BarItemLinkCollection.InsertItem(Int32 index, BarItemLinkBase itemLink)
     at DevExpress.Xpf.Bars.CustomizablePopupMenuBase.CustomizablePopupMenuItemLinkCollection.InsertItem(Int32 index, BarItemLinkBase itemLink)
     at System.Collections.ObjectModel.Collection`1.Add(T item)
     at DevExpress.Xpf.Bars.BarItemLinkBase.DevExpress.Xpf.Bars.IBarManagerControllerAction.Execute()
     at DevExpress.Xpf.Bars.BarManagerActionCollection.Execute()
     at DevExpress.Xpf.Bars.BarManagerActionContainer.Execute()
     at DevExpress.Xpf.Bars.BarManagerController.Execute()
     at DevExpress.Xpf.Bars.BarManagerMenuController.Execute()
     at DevExpress.Xpf.Grid.DataControlPopupMenu.ExecuteOriginationViewMenuController(Func`2 getMenuController)
     at DevExpress.Xpf.Grid.GridCellMenuInfo.ExecuteMenuController()
     at DevExpress.Xpf.Bars.CustomizablePopupMenuBase.CreateItems()
     at DevExpress.Xpf.Bars.CustomizablePopupMenuBase.RaiseOpening()
     at DevExpress.Xpf.Bars.BarPopupBase.OnIsOpenCoerce(Object value)
     at DevExpress.Xpf.Bars.PopupMenuBase.OnIsOpenCoerce(Object value)
     at DevExpress.Xpf.Bars.CustomizablePopupMenuBase.OnIsOpenCoerce(Object value)
     at DevExpress.Xpf.Bars.BarPopupBase.OnIsOpenCoerce(DependencyObject d, Object value)
     at System.Windows.DependencyObject.ProcessCoerceValue(DependencyProperty dp, PropertyMetadata metadata, EntryIndex& entryIndex, Int32& targetIndex, EffectiveValueEntry& newEntry, EffectiveValueEntry& oldEntry, Object& oldValue, Object baseValue, Object controlValue, CoerceValueCallback coerceValueCallback, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, Boolean skipBaseValueChecks)
     at System.Windows.DependencyObject.UpdateEffectiveValue(EntryIndex entryIndex, DependencyProperty dp, PropertyMetadata metadata, EffectiveValueEntry oldEntry, EffectiveValueEntry& newEntry, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType)
     at System.Windows.DependencyObject.SetValueCommon(DependencyProperty dp, Object value, PropertyMetadata metadata, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType, Boolean isInternal)
     at System.Windows.DependencyObject.SetValue(DependencyProperty dp, Object value)
     at System.Windows.Controls.Primitives.Popup.set_IsOpen(Boolean value)
     at DevExpress.Xpf.Bars.ContextMenuManager.ShowElementContextMenu(Object contextElement, Boolean openingFromKeyboard)
     at DevExpress.Xpf.Bars.ContextMenuManager.OpenContextMenu(Object sender, Boolean openingFromKeyboard)
     at DevExpress.Xpf.Bars.ContextMenuManager.OnContextMenuOpening(Object sender, ContextMenuEventArgs e)
     at System.Windows.Controls.ContextMenuEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)
     at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
     at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
     at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
     at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
     at System.Windows.UIElement.RaiseTrustedEvent(RoutedEventArgs args)
     at System.Windows.UIElement.RaiseEvent(RoutedEventArgs args, Boolean trusted)
     at System.Windows.Controls.PopupControlService.RaiseContextMenuOpeningEvent(IInputElement source, Double x, Double y, Boolean userInitiated)
     at System.Windows.Controls.PopupControlService.ProcessMouseUp(Object sender, MouseButtonEventArgs e)
     at System.Windows.Controls.PopupControlService.OnPostProcessInput(Object sender, ProcessInputEventArgs e)
     at System.Windows.Input.InputManager.RaiseProcessInputEventHandlers(ProcessInputEventHandler postProcessInput, ProcessInputEventArgs processInputEventArgs)
     at System.Windows.Input.InputManager.ProcessStagingArea()
     at System.Windows.Input.InputManager.ProcessInput(InputEventArgs input)
     at System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport)
     at System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawMouseActions actions, Int32 x, Int32 y, Int32 wheel)
     at System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr hwnd, WindowMessage msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
     at System.Windows.Interop.HwndSource.InputFilterMessage(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)

wpf 指定的元素已经是另一个元素的逻辑子元素。先断开连接”

提问by Antwan

采纳答案by atomaras

回答by Contango

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wpf 指定的元素已经是另一个元素的逻辑子元素。先断开连接”

提问by Antwan

采纳答案by atomaras

回答by Contango

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