AccordionItem.IsSelectedの値を設定できません

Question

WPFアコーディオンを設定する方法はありますか？そのアイテムはすべてデフォルトで折りたたまれています。

更新 私が実現したテンプレートによると、その項目がAccordionItemのIsSelectedプロパティで選択したものを、私は私が得る（ボタンクリックハンドラのコードから）このプロパティを設定しようとすると問題がありますInvalidOperationException以下：

Cannot modify the IsSelected property while item is locked. 

のStackTrace：

at System.Windows.Controls.AccordionItem.OnIsSelectedPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) in C:\dd\WPF_1\src\wpf\src\ControlsPack\WPFToolkit\Layout\Accordion\System\Windows\Controls\AccordionItem.cs:line 315 
    at System.Windows.DependencyObject.OnPropertyChanged(DependencyPropertyChangedEventArgs e) 
    at System.Windows.FrameworkElement.OnPropertyChanged(DependencyPropertyChangedEventArgs e) 
    at System.Windows.DependencyObject.NotifyPropertyChange(DependencyPropertyChangedEventArgs args) 
    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.AccordionItem.set_IsSelected(Boolean value) in C:\dd\WPF_1\src\wpf\src\ControlsPack\WPFToolkit\Layout\Accordion\System\Windows\Controls\AccordionItem.cs:line 284 
    at WpfSampleApplication.MainWindow.btn_Click(Object sender, RoutedEventArgs e) in d:\users\shimmy\documents\visual studio 2010\Projects\WpfSampleApplication\MainWindow.xaml.vb:line 9 
    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.RaiseEvent(RoutedEventArgs e) 
    at System.Windows.Controls.Primitives.ButtonBase.OnClick() 
    at System.Windows.Controls.Button.OnClick() 
    at System.Windows.Controls.Primitives.ButtonBase.OnMouseLeftButtonUp(MouseButtonEventArgs e) 
    at System.Windows.UIElement.OnMouseLeftButtonUpThunk(Object sender, MouseButtonEventArgs e) 
    at System.Windows.Input.MouseButtonEventArgs.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.ReRaiseEventAs(DependencyObject sender, RoutedEventArgs args, RoutedEvent newEvent) 
    at System.Windows.UIElement.OnMouseUpThunk(Object sender, MouseButtonEventArgs e) 
    at System.Windows.Input.MouseButtonEventArgs.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.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) 
    at System.Windows.Threading.Dispatcher.InvokeImpl(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 WpfSampleApplication.Application.Main() in d:\users\shimmy\documents\visual studio 2010\Projects\WpfSampleApplication\obj\x86\Debug\Application.g.vb:line 64 
    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.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx) 
    at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) 
    at System.Threading.ThreadHelper.ThreadStart() 

Answer 1

あなたがトンで選択された項目を制御することができますコントロールAccordionのプロパティーSelectedIndexとSelectedItemです。

あなたは崩壊したとして、最初はすべての項目を表示するために最初の項目として、非可視AccordionItemを置くことができます。

<toolkit:AccordionItem Visibility="Collapsed"/> 

特定の項目を開くには、LoadedハンドラでSelectedIndexプロパティを設定します。

<toolkit:Accordion> 
    <i:Interaction.Triggers> 
     <i:EventTrigger EventName="Loaded"> 
      <ei:ChangePropertyAction PropertyName="SelectedIndex" Value="2"/> 
     </i:EventTrigger> 
    </i:Interaction.Triggers> 

編集：

"のxmlns：i" は、名前空間はWPF4の一部であるSystem.Windows.Interactivityを指します。あなたが行動を使用している場合、またはあなたはXAMLですべてを行うことができます「のxmlns：EI」名前空間は、の一部であるMicrosoft.Expression.Interactionsを参照：

• Microsoft Expression Blend Software Development Kit (SDK) for .NET 4

あなたのプロジェクトへの参照を追加した後、あなたは、名前空間を設定するためにこれを使用することができます。

<Window ... 
    xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity" 
    xmlns:ei="http://schemas.microsoft.com/expression/2010/interactions" 
    ...>