ListPicker崩溃

Question

我有一个具有以下结构的ListPicker:

toolkit:ListPicker x:Name="mListPicker" HorizontalAlignment="Right" Margin="0,75,43,0" Width="100" VerticalAlignment="Top">
< toolkit:ListPickerItem Content="5"/>
< toolkit:ListPickerItem Content="10"/>
< toolkit:ListPickerItem Content="15"/>
< toolkit:ListPickerItem Content="20"/>
< toolkit:ListPickerItem Content="25"/>
< toolkit:ListPickerItem Content="30"/>
< /toolkit:ListPicker>

每当我尝试运行此命令时,会出现以下消息:

System.Windows.Markup.XamlParseException occurred
  Message= [Line: 0 Position: 0]
   --- Inner Exception ---
The parameter is incorrect. 

  LineNumber=0
  LinePosition=0
  StackTrace:
       at MS.Internal.XcpImports.MethodEx(IntPtr ptr, String name, CValue[] cvData)
       at MS.Internal.XcpImports.MethodEx(DependencyObject obj, String name)
       at MS.Internal.XcpImports.FrameworkElement_ApplyTemplate(FrameworkElement frameworkElement)
       at System.Windows.FrameworkElement.ApplyTemplateInternal()
       at System.Windows.Controls.ScrollContentPresenter.HookupScrollingComponents()
       at System.Windows.Controls.ScrollContentPresenter.OnApplyTemplate()
       at System.Windows.FrameworkElement.OnApplyTemplate(IntPtr nativeTarget)
       at MS.Internal.XcpImports.MeasureNative(IntPtr element, Single inWidth, Single inHeight)
       at MS.Internal.XcpImports.UIElement_Measure(UIElement element, Size availableSize)
       at System.Windows.UIElement.Measure(Size availableSize)
       at System.Windows.Controls.ScrollViewer.MeasureOverride(Size constraint)
       at System.Windows.FrameworkElement.MeasureOverride(IntPtr nativeTarget, Single inWidth, Single inHeight, Single& outWidth, Single& outHeight)
       at MS.Internal.XcpImports.MeasureOverrideNative(IntPtr element, Single inWidth, Single inHeight, Single& outWidth, Single& outHeight)
       at MS.Internal.XcpImports.FrameworkElement_MeasureOverride(FrameworkElement element, Size availableSize)
       at System.Windows.FrameworkElement.MeasureOverride(Size availableSize)
       at System.Windows.FrameworkElement.MeasureOverride(IntPtr nativeTarget, Single inWidth, Single inHeight, Single& outWidth, Single& outHeight)
  InnerException: System.ArgumentException
       Message=The parameter is incorrect. 
       StackTrace:
            at MS.Internal.XcpImports.CheckHResult(UInt32 hr)
            at MS.Internal.XcpImports.SetValue(INativeCoreTypeWrapper obj, DependencyProperty property, DependencyObject doh)
            at MS.Internal.XcpImports.SetValue(INativeCoreTypeWrapper doh, DependencyProperty property, Object obj)
            at System.Windows.DependencyObject.SetObjectValueToCore(DependencyProperty dp, Object value)
            at System.Windows.DependencyObject.SetValueInternal(DependencyProperty dp, Object value, Boolean allowReadOnlySet, Boolean isSetByStyle, Boolean isSetByBuiltInStyle, PropertyInvalidationReason reason)
            at System.Windows.DependencyObject.SetValueInternal(DependencyProperty dp, Object value)
            at System.Windows.DependencyObject.SetValue(DependencyProperty dp, Object value)
            at System.Windows.Controls.ContentControl.set_Content(Object value)
            at System.Windows.Controls.ItemsControl.PrepareContainerForItemOverride(DependencyObject element, Object item)
            at System.Windows.Controls.Primitives.Selector.PrepareContainerForItemOverride(DependencyObject element, Object item)
            at System.Windows.Controls.ItemsControl.MS.Internal.Controls.IGeneratorHost.PrepareItemContainer(DependencyObject container, Object item)
            at System.Windows.Controls.ItemContainerGenerator.System.Windows.Controls.Primitives.IItemContainerGenerator.PrepareItemContainer(DependencyObject container)
            at System.Windows.Controls.ItemsControl.AddVisualChild(Int32 index, DependencyObject container, Boolean needPrepareContainer)
            at System.Windows.Controls.ItemsControl.AddContainers()
            at System.Windows.Controls.ItemsControl.RecreateVisualChildren(IntPtr unmanagedObj)
            at MS.Internal.XcpImports.MethodExNative(IntPtr context, IntPtr element, UInt32 cString, String name, UInt32 cParams, IntPtr pParams, CValue& outval, Int32& typeIndex)
            at MS.Internal.XcpImports.MethodEx(IntPtr ptr, String name, CValue[] cvData)
            at MS.Internal.XcpImports.MethodEx(DependencyObject obj, String name)
            at MS.Internal.XcpImports.FrameworkElement_ApplyTemplate(FrameworkElement frameworkElement)
            at System.Windows.FrameworkElement.ApplyTemplateInternal()
            at System.Windows.Controls.ScrollContentPresenter.HookupScrollingComponents()
            at System.Windows.Controls.ScrollContentPresenter.OnApplyTemplate()
            at System.Windows.FrameworkElement.OnApplyTemplate(IntPtr nativeTarget)
            at MS.Internal.XcpImports.MeasureNative(IntPtr element, Single inWidth, Single inHeight)
            at MS.Internal.XcpImports.UIElement_Measure(UIElement element, Size availableSize)
            at System.Windows.UIElement.Measure(Size availableSize)
            at System.Windows.Controls.ScrollViewer.MeasureOverride(Size constraint)
            at System.Windows.FrameworkElement.MeasureOverride(IntPtr nativeTarget, Single inWidth, Single inHeight, Single& outWidth, Single& outHeight)
            at MS.Internal.XcpImports.MeasureOverrideNative(IntPtr element, Single inWidth, Single inHeight, Single& outWidth, Single& outHeight)
            at MS.Internal.XcpImports.FrameworkElement_MeasureOverride(FrameworkElement element, Size availableSize)
            at System.Windows.FrameworkElement.MeasureOverride(Size availableSize)
            at System.Windows.FrameworkElement.MeasureOverride(IntPtr nativeTarget, Single inWidth, Single inHeight, Single& outWidth, Single& outHeight)

它说元素已经是另一个元素了.

但是如果我删除最后一项并且只在选择器中保留五个项目,那么它可以正常工作.我错了什么？

Answer 1

将ListPicker的ItemCountThreshold属性设置为大于6的值(默认情况下,它列出五个或更少的项).你需要类似的东西:

 <toolkit:ListPicker ItemCountThreshold="10">
                <toolkit:ListPickerItem Content="1" />
                <toolkit:ListPickerItem Content="2"/>
                <toolkit:ListPickerItem Content="3"/>
                <toolkit:ListPickerItem Content="4"/>
                <toolkit:ListPickerItem Content="5"/>
                <toolkit:ListPickerItem Content="6"/>
            </toolkit:ListPicker>

ItemCountThreshold:ItemCountThreshold是int类型的依赖项属性.它指定将在Expanded模式下显示的最大项目数.默认情况下,具有五个或更少项目的列表就地扩展,而具有更多项目的列表切换到全屏选择界面.它也可以设置为0以切换完全模式或非常大的数字来切换扩展模式.