Problems with ShellNamespaceTreeControl

[tajbender]

Hello David,

I just wanted to integrate ShellNamespaceTreeControl but found issues:

1. When using the Designer, I get the following MessageBox:

This happens after dropping the Control onto its form in the Designer, and hitting Start the first time.

2. AccessViolationException:

Describe the bug
While playing around with the TreeView, trying to expand this and that Node, I sometimes get an AccessViolationException. This isn't often the case, about 20-30 tries that went okay before the exception occurs.

Don't think it has to do with a specific folder type, and when, I couldn't find the pattern this makes it happen.

Here is the debugger's "View Details" output:

	Name	Value	Type
◢	$exception	{"Attempted to read or write protected memory. This is often an indication that other memory is corrupt."}	System.AccessViolationException
	▶ Data	{System.Collections.ListDictionaryInternal}	System.Collections.IDictionary {System.Collections.ListDictionaryInternal}
	HResult	0x80004003	int
	HelpLink	null	string
	IPForWatsonBuckets	0x00000000	System.UIntPtr
	▶ InnerException	null	System.Exception
	IsTransient	false	bool
	Message	"Attempted to read or write protected memory. This is often an indication that other memory is corrupt."	string
	RemoteStackTrace	null	string
	Source	"System.Windows.Forms"	string
	StackTrace	" at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)\r\n at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr dwComponentID, Int32 reason, Int32 pvLoopData)\r\n at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)\r\n at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)\r\n at System.Windows.Forms.Application.Run(Form mainForm)\r\n at Vanara_ShellNamespaceTreeControl.Program.Main() in S:\[Git.Workspace]\[Test-Projekte]\Vanara-ShellNamespaceTreeControl\Program.cs:line 19"	string
	▶ TargetSite	{IntPtr DispatchMessageW(MSG ByRef)}	System.Reflection.MethodBase {System.Reflection.RuntimeMethodInfo}
	▶ WatsonBuckets	{byte[0x000015f0]}	object {byte[]}
	_HResult	0x80004003	int
	_accessType	0x00000000	int
	_className	null	string
	▶ _data	{System.Collections.ListDictionaryInternal}	System.Collections.IDictionary {System.Collections.ListDictionaryInternal}
	_dynamicMethods	null	object
	_exceptionMethod	null	System.Reflection.MethodBase
	_exceptionMethodString	null	string
	_helpURL	null	string
	▶ _innerException	null	System.Exception
	_ip	0x65ce2f9f	System.IntPtr
	_ipForWatsonBuckets	0x00000000	System.UIntPtr
	_message	"Attempted to read or write protected memory. This is often an indication that other memory is corrupt."	string
	_remoteStackIndex	0x00000000	int
	_remoteStackTraceString	null	string
	▶ _safeSerializationManager	{System.Runtime.Serialization.SafeSerializationManager}	System.Runtime.Serialization.SafeSerializationManager
	_source	"System.Windows.Forms"	string
	▶ _stackTrace	{sbyte[0x000000c0]}	object {sbyte[]}
	_stackTraceString	null	string
	_target	0x00000024	System.IntPtr
	▶ _watsonBuckets	{byte[0x000015f0]}	object {byte[]}
	_xcode	0xc0000005	int
	_xptrs	0x00bad36c	System.IntPtr
	◢ Static members
	_COMPlusExceptionCode	0xe0434352	int
	s_EDILock	{object}	object

What code is involved

Just a plain Windows Forms window, nothing in it except the ShellNamespaceTreeControl. BTW, this also happened to me using the Unit Test App.

Using Vanara v3.2.12, .net Framework 4.6 on a Windows 10 machine.

Thank you very much in advance, regards,

tajbender

[dahall]

I think I addressed the first problem with a property decoration. However, using the unit test app I cannot replicate the second issue. I've expanded and contracted system folders, namespace folders, zip files, etc. on my system about 50 times and never see an exception. If you're able to reproduce with consistency, please let me know how.

[tajbender]

Thanks for your quick reply.

In the meantime I found the second issue only arises when built in Debug configuration and being run within the VS-Debugger. Using release config wipes the bug away...

Nice, I love those bugs. Enable native code debugging brought those additional Infos, I'm not to confident they'll help you, but perhaps you have any idea - I don't 😞

Exception thrown at 0x66252F9F (comctl32.dll) in ExplorerBrowser.exe: 0xC0000005: Access violation reading location 0x00000024.

[dahall]

I can't replicate it, even with your instructions. Since I think I fixed your first issue (please confirm) with the release yesterday, let me know if I can close this.

[tajbender]

Sure you can close this. Any Ideas what I can do to narrow the problem on my machine down?

[dahall]

It is interesting to look at the logs. It appears the fault is in ComCtl32.dll, which is the hosting dll for the underlying TreeView control. That makes me think it may have something to do with message handling (or event handling in the COM wrapper). I'll take a closer look at anything in my code in that space, but it is pretty light. It may be a problem with the INameSpaceTreeControl implementation. I'll leave this open and let you know what I find.

[tajbender]

Thank you so much. In the meantime, I'll also do some deeper investigations and will let you know if I have any more idea.

However, David, please don't spend too much of your time while digging into this. Perhaps it's my machine that suffers of some kind of bad configuration, although it's a very clean developer machine with TortoiseGIT, Visual Studio, Kaspersky AV and some more development tools, sort of nothing special.

However, thanks for supporting me.

[tajbender]

@dahall: I have an Idea: Originally, I placed the Tree into a SplitContainer. Now I removed the surrounding SplitContainer, et voila. As far I can tell now, after some minutes of testing, it works at least much more stable es before.. Any ideas on this?

Are System.Windows.Forms.SplitContainer Controls buggy as hell? I didn't use them too much, to be honest.

However, I'm very sorry for bothering you with this :(

EDIT: Although that doesn't clarify why the test-app is crashing on my machine 😡

[tajbender]

@dahall: Now, I'm almost pretty sure, about 50% 😞, it has to do with Dock property. As soon as I set the Dock-Property to Left, Right, Top, Bottom, Fill problems arise and I get hard crashes. Reverting back to DockStyle.None and it works as expected.

Can you confirm this on your machine?

[dahall]

My testing app has Dock = Fill and it works without error even with automated testing that changes the form size 50 times and selects 50 items. Sorry.

[tajbender]

Hi David, what Framework version are you using for your testing?

[dahall]

4.5.2

[tajbender]

Okay, thank you very much so far. I'll reinstall my machine eventually and hope this will help.

Thank you very much!

[dahall]

I was doing some testing on the events today and found that a number of them return a seemingly wrong value to the interface. I'm playing with values now since the docs are not very good. I'll let you know when I have something to test.

[dahall]

I can't figure out how, but I just got your exception. I'm opening this up until I can figure it out.

[tajbender]

Maybe it's just an InvokeRequired(), that's missing somewhere? Just a thought.

By the way, how can I cast a Shell32.ShellFolder object into an IShellFolder? IShellFolder member is protected as you know, so how do I get it?

[dahall]

I've had to redo much of the ShellNamespaceTreeControl class and am still working through one final bug.

On you second question, there wasn't a way to get the underlying IShellFolder instance. I just added a property to allow it.

[dahall]

It's working much better now, but I wouldn't consider it "production". If you really need it and have time to work on it, please submit a PR.

[dahall]

If you have time, please give the update a test. You can add https://ci.appveyor.com/nuget/vanara-prerelease to your NuGet package repository list and then pull the 3.2.14 packages.

[tajbender]

Hello David,

thank you so much! I've played around with this version and it works much more stable now. Great work!

However, I found one (small) Issue: When navigating to a sub-folder of Desktop\Libraries in the Tree, like Desktop\Libraries\Documents or Desktop\Libraries\Pictures, I get an exception when accessing the SelectedItem:

System.IO.FileLoadException
HResult=0x80070020
Message=The process cannot access the file because it is being used by another process. (Exception from HRESULT: 0x80070020)
Source=
StackTrace:

Any Idea? Thank you very much again, and have I nice weekend 🌞

Regards,
tajbender

[tajbender]

It's working much better now, but I wouldn't consider it "production". If you really need it and have time to work on it, please submit a PR.

Okay, I'll investigate this. Thank you so much!

[dahall]

This is now officially published to NuGet