WPF Tree View Freeze / Hang

[pjchristmas]

• .NET Framework 4.8 with latest patch that claimed to fix similar sounding bug.
• Windows version: (winver): Win10 1803

Problem description:
Identical to issue 1962
but not fixed by update listed there.
We have a virtualized Tree View with up to 30k items. Going to the bottom and scrolling up 51 times (or using scroll wheel) will cause it to freeze. If I leave it up for an hour it will usually come back(or maybe it's just logging out and back in that kicks it out of the layout loop)
We've tried changing the virtualization settings (ScrollUnit, VirtualizationCacheLength, VirtualizationCacheLengthUnit and VirtualizationMode.Recycling) but none had any effect.

Minimal repro:
Attached app, just modified the one from previous posting and added reproducing data.
HangTest.zip

Looking for a hero @SamBent

[SamBent]

@pjchristmas - Just saw this, and looked at your repro just enough to confirm that it hangs, but for a different root cause than in 1962. I don't know the root cause yet.

Can you speak to the business case for fixing this in .NET servicing? How often does it happen, when did it start happening, what fraction of the data sets hit it, is there a reliable workaround - that sort of thing. (You've alluded to some of the already, I just want to fill in more blanks.)

BTW, I didn't get an email six days ago when you tagged me. Perhaps GitHub only sends email when you tag me in a new comment, not when you add the tag in an edit of an existing comment?

[pjchristmas]

Business case: This is important to key products/customers at National Instruments. We will be elevating through service channels as well.
Reproducing: It happens every time (you do upward scrolling) for certain data sets. The particulars of the dataset are customer driven, and we've seen it in a number of their files, but not all. Some combination of size and shape of tree seem to matter.
Workaround: We don't have one yet. If you have ideas, we'd love to try them. Our datasets get big enough that turning off virtualization is not an option.

Thanks for looking into this @SamBent .

[BradenCalderMurphy]

Hi, have there been any updates with regards to this?
I'm using .NET 4.8 and still get the freezing on my WPF treeview using VirtualizationMode

[BradenCalderMurphy]

So I started using https://sourceforge.net/projects/treeviewadv/ (it's on nuget) in the meantime but actually it's great, super fast and responsive. I used it in WPF with the "WindowsFormsHost"

[SamBent]

We've fixed a set of issues exposed by this bug (and variants supplied by @pjchristmas via MS customer support). Expect to see these fixes soon in a .NET Framework update and in .NET Core.

[ghost]

@dotnet/wpf-developers, It's time to give an update to the community.

[ghost]

@dotnet/wpf-developers, It's time to give an update to the community.

[ghost]

@dotnet/wpf-developers, It's time to give an update to the community.

[fabiant3]

@SamBent - let's check in the .NET Core fixes and update this thread.

[ghost]

@dotnet/wpf-developers, It's time to give an update to the community.

[ghost]

@dotnet/wpf-developers, It's time to give an update to the community.

[ghost]

@dotnet/wpf-developers, It's time to give an update to the community.

[ghost]

@dotnet/wpf-developers, It's time to give an update to the community.

[ghost]

@dotnet/wpf-developers, It's time to give an update to the community.

[SamBent]

Fix ported to 3.1.19, 5.0.0, and 6.0.