InvalidOperationException at MS.Internal.Data.PropertyPathWorker.CheckReadOnly(Object item, Object info) at MS.Internal.Data.PropertyPathWorker.ReplaceItem(Int32 k, Object newO, Object parent) at MS.Internal.Data.PropertyPathWorker.UpdateSourceValueState(Int32 k, ICollectionView collectionView, Object newValue, Boolean isASubPropertyChange) at MS.Internal.Data.ClrBindingWorker.AttachDataItem() at System.Windows.Data.BindingExpression.Activate(Object item) at System.Windows.Data.BindingExpression.AttachToContext(AttachAttempt attempt) at System.Windows.Data.BindingExpression.MS.Internal.Data.IDataBindEngineClient.AttachToContext(Boolean lastChance) at MS.Internal.Data.DataBindEngine.Task.Run(Boolean lastChance) at MS.Internal.Data.DataBindEngine.Run(Object arg) at System.Windows.ContextLayoutManager.fireLayoutUpdateEvent() at System.Windows.ContextLayoutManager.UpdateLayout() at System.Windows.ContextLayoutManager.UpdateLayoutCallback(Object arg) at System.Windows.Media.MediaContext.FireInvokeOnRenderCallbacks() at System.Windows.Media.MediaContext.RenderMessageHandlerCore(Object resizedCompositionTarget) at System.Windows.Media.MediaContext.RenderMessageHandler(Object resizedCompositionTarget) at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs) at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)