我正在使用telerik radanimationcontrol以及一些第三方附加属性来在wpf中创建adRotator . 第三方附加属性有一个文档说明广告显示的当前索引是在SelectedIndexProperty中返回的 . 但是，我试图使用以下方法访问SelectedIndexProperty .
long si =(long)TranControl.GetValue(AdRotatorExtensions.AdRotatorExtensions.CurrentSelectedIndexProperty) ;
上面的语句导致InvalidCastException . 任何人都可以告诉我如何通过代码后面访问该属性 . 我对radAnimationControl的xaml标记如下
<telerik:RadTransitionControl Name="TranControl" adRotator:AdRotatorExtensions.ItemChangeDelay="0:0:3"
adRotator:AdRotatorExtensions.CurrentSelectedIndex="0"
VerticalAlignment="Center"
HorizontalAlignment="Center" MouseLeftButtonDown="RadTransitionControl_MouseLeftButtonDown">
<telerik:RadTransitionControl.Transition>
<telerik:MotionBlurredZoomTransition />
</telerik:RadTransitionControl.Transition>
<adRotator:AdRotatorExtensions.ItemsSource>
<adRotator:AdsCollection >
<Image Source="/Banners/1_AJAX_Slide.jpg" />
<Image Source="/Banners/2_MVC_Slide.jpg" />
<Image Source="/Banners/3_SL_Slide.jpg" />
<Image Source="/Banners/4_WF_Slide.jpg" />
<Image Source="/Banners/5_WPF_Slide.jpg" />
<Image Source="/Banners/6_REP_Slide.jpg" />
<Image Source="/Banners/7_ORM_Slide.jpg" />
<Image Source="/Banners/8_JC_Slide.jpg" />
<Image Source="/Banners/9_JM_Slide.jpg" />
</adRotator:AdsCollection>
</adRotator:AdRotatorExtensions.ItemsSource>
</telerik:RadTransitionControl>
另外，请告诉我是否可以将itemsource设置为observablecollection，它是自定义类的集合，并获取自定义类引用而不是SelectedIndex作为int .
我试过this link但没有帮助我 .
我试过的另一件事情如下
int currentSelectedIndex = AdRotatorExtensions.AdRotatorExtensions.GetCurrentSelectedIndex(null);
GetCurrentSelectedIndex定义为
public static readonly DependencyProperty CurrentSelectedIndexProperty =
DependencyProperty.RegisterAttached("CurrentSelectedIndex", typeof(int), typeof(AdRotatorExtensions), new PropertyMetadata(-1, OnCurrentSelectedIndexChanged));
private static void OnCurrentSelectedIndexChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
UpdateCurrentlySelectedItem(d);
}
private static void UpdateCurrentlySelectedItem(DependencyObject element)
{
var contentControl = element as ContentControl;
var source = GetItemsSource(element);
// If there is no source we shouldn't do anything.
if (source == null) return;
// Find the actual index to be selected (if outside the boundaries of the collection)
// and find the actual element to be selected.
var convertedSource = source.Cast<object>();
var currentIndex = GetCurrentSelectedIndex(element);
var elementToSelect = convertedSource.ElementAtOrDefault(currentIndex);
// Update the cotnent of the ContentControl if attached to a ContentControl.
if (contentControl != null)
{
contentControl.Content = elementToSelect;
}
}
public static int GetCurrentSelectedIndex(DependencyObject obj)
{
return (int)obj.GetValue(CurrentSelectedIndexProperty);
}
public static readonly DependencyProperty CurrentSelectedIndexProperty = DependencyProperty.RegisterAttached（“CurrentSelectedIndex”，typeof（int），typeof（AdRotatorExtensions），new PropertyMetadata（-1，OnCurrentSelectedIndexChanged））
在调用int currentSelectedIndex = AdRotatorExtensions.AdRotatorExtensions.GetCurrentSelectedIndex（null）;时，堆栈跟踪异常发生
at AdRotatorExtensions.AdRotatorExtensions.GetCurrentSelectedIndex(DependencyObject obj) in G:\Raj\Kiosk\AdRotatorExample Demo project\AdRotatorExtensions\AdRotatorExtensions.cs:line 47
at AdRotatorExampleWPF.MainWindow.RadTransitionControl_MouseLeftButtonDown(Object sender, MouseButtonEventArgs e) in G:\Raj\Kiosk\AdRotatorExample Demo project\AdRotatorExampleWPF\MainWindow.xaml.cs:line 19
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.CrackMouseButtonEventAndReRaiseEvent(DependencyObject sender,
调用异常发生的堆栈跟踪调用long si =（long）TranControl.GetValue（AdRotatorExtensions.AdRotatorExtensions.CurrentSelectedIndexProperty）;:
at AdRotatorExampleWPF.MainWindow.RadTransitionControl_MouseLeftButtonDown(Object sender, MouseButtonEventArgs e) in G:\Raj\Kiosk\AdRotatorExample Demo project\AdRotatorExampleWPF\MainWindow.xaml.cs:line 20
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.CrackMouseButtonEventAndReRaiseEvent(DependencyObject sender, MouseButtonEventArgs e)
at System.Windows.UIElement.OnMouseDownThunk(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.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, Int32 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, Boolean isSingleParameter)
at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler)
at System.Windows.Threading.Dispatcher.WrappedInvoke(Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler)
at System.Windows.Threading.Dispatcher.InvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Boolean isSingleParameter)
at System.Windows.Threading.Dispatcher.Invoke(DispatcherPriority priority, Delegate method, Object arg)
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 AdRotatorExampleWPF.App.Main() in G:\Raj\Kiosk\AdRotatorExample Demo project\AdRotatorExampleWPF\obj\x86\Debug\App.g.cs:line 0
at System.AppDomain._nExecuteAssembly(Assembly 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)
at System.Threading.ThreadHelper.ThreadStart()