SetFinalSizeMaxDiscrepancy getting stuck in an infinite loop in .NET 4.7.1
I’ve received several dump files from my customers where the top of the call stack is in either in SetFinalSizeMaxDiscrepancy, or a function that SetFinalSizeMaxDiscrepancy is calling. It appears that it is stuck in the for(bool runPhase2and3=true; runPhase2and3;) loop. I can’t step through the code, so tracing down why it is stuck is very difficult.
I created a thread on this topic in the MSDN Forum and Franklin Chen replied with:
"We notice that the Telemetry Bug Tracker has filed a Busy Hang failure in PresentationFramework.dll recently, if we can get the dump file you mentioned, it will be helpful to locate this root cause."
It is hard to re-create the hang, but I have plenty of dump files to provide as examples.
Thanks
Dan
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Similar bug: WPF Resizing a Grid still hangs
https://developercommunity.visualstudio.com/content/problem/293898/wpf-resizing-a-grid-still-hangs.html
Also getting dump files with SetFinalSizeMaxDiscrepancy at the top of the stack. Can also provide dump file.
Adding the following to the app .config file fixed it for us:<AppContextSwitchOverridesvalue="Switch.System.Windows.Controls.Grid.StarDefinitionsCanExceedAvailableSpace=true"/>
I can reproduce this bug reliably in Framework 4.7.2 ... And it was not hard to hit!
I have created a repository on GitHub with a simple project that will reliably hang. It is here:
https://github.com/steevcoco/Net472SetFinalSizeMaxDiscrepancyHangs
... In fact, it requires using a DependencyProperty, which I ONLY used in code (not in XAML --- and it so happens to be defined on a UIElement and not a FrameworkElement; don't know it that also contributes).
... For anyone watching this ... I have also discovered that the bug seems to only appear when Windows Text Scaling is enabled --- it is set to 116% on this machine (which fails every time in the above project when text scaling is enabled; and will run when scaling is turned off). This is a 120 dpi 2880x1620 laptop.
A GitHub issue is here:
https://github.com/Microsoft/dotnet/issues/604#issuecomment-427465499
Microsoft has recognized this as a bug, but it is unknown what version they will be releasing their fix in. In the meantime, adding <AppContextSwitchOverridesvalue="Switch.System.Windows.Controls.Grid.StarDefinitionsCanExceedAvailableSpace=true"/> to the app.config file is their solution.
Ew ... I have a project where I can't modify the config ---- a "Plugin" type solution.
Is it possible to set this in code?
I think AppContext.SetSwitch is your answer. https://docs.microsoft.com/en-us/dotnet/api/system.appcontext.setswitch?view=netframework-4.7.2
Glad others found this as well. We just stepped up to Framework 4.7.2 and yes, it is easy to reproduce. I just wonder if the fix mentioned on GitHub really only applied to rows? I see it for a column scenario.
Anyway, for now the fix with the switch does the trick. Thumbs up for pointing this out.
I wonder why one would like to have star sized columns / rows exceed the available space? I ALWAYS rely on them not being pushed over the edge.
