Unhandled Error in Silverlight Application Object reference not set to an instance of an object

[Vlad]

I am getting a very strange error that I cannot resolve:

Message: Unhandled Error in Silverlight Application Object reference not set to an instance of an object.   at Telerik.Windows.Controls.RadBook.OnCurrentSheetIndexChanged(Int32 newValue, Int32 oldValue)
   at Telerik.Windows.Controls.RadBook.OnRightPageIndexChanged(Int32 rightPageIndex)
   at Telerik.Windows.Controls.RadBook.OnRightPageIndexPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
   at Telerik.Windows.PropertyMetadata.<>c__DisplayClass1.<Create>b__0(DependencyObject d, DependencyPropertyChangedEventArgs e)
   at System.Windows.DependencyObject.RaisePropertyChangeNotifications(DependencyProperty dp, Object oldValue, Object newValue)
   at System.Windows.DependencyObject.UpdateEffectiveValue(DependencyProperty property, EffectiveValueEntry oldEntry, EffectiveValueEntry& newEntry, ValueOperation operation)
   at System.Windows.DependencyObject.SetValueInternal(DependencyProperty dp, Object value, Boolean allowReadOnlySet)
   at Telerik.Windows.Controls.RadBook.set_RightPageIndex(Int32 value)
   at HotmailBackToSchool.MainPage.OpenTipPage1(Object sender, 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.Controls.Control.OnMouseLeftButtonUp(Control ctrl, EventArgs e)
   at MS.Internal.JoltHelper.FireEvent(IntPtr unmanagedObj, IntPtr unmanagedObjArgs, Int32 argsTypeIndex, Int32 actualArgsTypeIndex, String eventName)

My code is pretty basic. I cannot find anything wrong in here:

private

void OpenPage1(object sender, System.Windows.RoutedEventArgs e)

{

 this.Book.RightPageIndex = 1;

}

 It happens while the app in RightPageIndex = 11, RightPageIndex = 9, or RightPageIndex = 7 and I cleck a button to open forst page.
I tried suggested fix from other post:

this

 

 

.Dispatcher.BeginInvoke(new Action(() => { Book.RightPageIndex = 1; }));

 

It does not solve this issue. I am wondering if it is possible to fix. Please help. Thank you in advance!

[Petar Mladenov]

Hi Vlad,

I am unable to reproduce this issue. Could you please examine my test project and let me know if I have missed something? You can also modify it so that it shows the problem. Thank you in advance for your cooperation.

Best wishes,
Petar Mladenov
the Telerik team