What is the strangest WPF bug you have seen?

I want to gather here the hard-to-reproduce WPF bugs along with their solution. So post them only if you have a solution for them, you can post just a link to them.

I found one of these, and I put it here because I didn't found an easy way to put code on a blog yet (and I tried a few of those code formatters).

Test1: Start the following app, move the window, all is fine.

<Window x:Class="WpfApplication1.Window1"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="Window1"
        Height="300"
        Width="300">
    <TextBlock>
        <Hyperlink/>
    </TextBlock>
</Window>

Test2: Start Narrator (or another automation client), repeat Test1, you get a crash.

Test3: Replace the

<Hyperlink/>

line with

<Hyperlink>h</Hyperlink>

,repeat Test2, no crash. I found the solution for this here.

The stack trace of the crash is:

System.ArgumentOutOfRangeException was unhandled
  Message="The parameter value must be greater than zero.\r\nParameter name: textLength"
  Source="PresentationCore"
  ParamName="textLength"
  StackTrace:
       at MS.Internal.TextFormatting.TextMetrics.FullTextLine.GetTextBounds(Int32 firstTextSourceCharacterIndex, Int32 textLength)
       at MS.Internal.Text.Line.GetRangeBounds(Int32 cp, Int32 cch, Double xOffset, Double yOffset)
       at System.Windows.Controls.TextBlock.GetTightBoundingGeometryFromTextPositions(ITextPointer startPosition, ITextPointer endPosition)
       at MS.Internal.Documents.TextParagraphView.GetTightBoundingGeometryFromTextPositions(ITextPointer startPosition, ITextPointer endPosition)
       at MS.Internal.Documents.TextViewBase.System.Windows.Documents.ITextView.GetTightBoundingGeometryFromTextPositions(ITextPointer startPosition, ITextPointer endPosition)
       at System.Windows.Automation.Peers.TextElementAutomationPeer.CalculateVisibleRect(ITextView textView, TextElement textElement, TextPointer startPointer, TextPointer endPointer)
       at System.Windows.Automation.Peers.TextElementAutomationPeer.IsOffscreenCore()
       at System.Windows.Automation.Peers.AutomationPeer.UpdateSubtree()
       at System.Windows.Automation.Peers.AutomationPeer.UpdateSubtree()
       at System.Windows.Automation.Peers.AutomationPeer.UpdateSubtree()
       at System.Windows.Automation.Peers.AutomationPeer.UpdatePeer(Object arg)
       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.DispatcherOperation.InvokeImpl()
       at System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext(Object state)
       at System.Threading.ExecutionContext.runTryCode(Object userData)
       at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData)
       at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Windows.Threading.DispatcherOperation.Invoke()
       at System.Windows.Threading.Dispatcher.ProcessQueue()
       at System.Windows.Threading.Dispatcher.WndProcHook(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.CallWindowProc(IntPtr wndProc, IntPtr hWnd, Int32 msg, IntPtr wParam, IntPtr lParam)
       at MS.Win32.HwndSubclass.DefWndProcWrapper(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
       at MS.Win32.UnsafeNativeMethods.CallWindowProc(IntPtr wndProc, IntPtr hWnd, Int32 msg, IntPtr wParam, IntPtr lParam)
       at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
       at MS.Win32.UnsafeNativeMethods.CallWindowProc(IntPtr wndProc, IntPtr hWnd, Int32 msg, IntPtr wParam, IntPtr lParam)
       at MS.Win32.HwndSubclass.DefWndProcWrapper(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
       at MS.Win32.UnsafeNativeMethods.CallWindowProc(IntPtr wndProc, IntPtr hWnd, Int32 msg, IntPtr wParam, IntPtr lParam)
       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 WpfApplication1.App.Main() in E:\Documents\Visual Studio 2008\Projects\WpfApplication1\WpfApplication1\obj\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()
  InnerException:

ansaurus

tags:

views:

answers:

What is the strangest WPF bug you have seen?

related questions