[Bug]: KryptonTreeView can throw exception on changing palette via KryptonManager

[ZXBITLES]

Describe the bug
Exception can be thrown in KryptonTreeView by method WndProc, when KryptonTreeView is visible (has expanded nodes) and palette changed.

To Reproduce

1. Create a form with KryptonTreeView.
2. Fill KryptonTreeView with some nodes.
3. Add KryptonManager to a form.
4. Start app.
5. Expand few nodes in KryptonTreeView.
6. Change palette via KryptonManager.
7. Exception will be thrown in KryptonTreeView.cs at
   protected override void WndProc(ref Message m) {
   ...
   default:
   base.WndProc(ref m);
   break;
   ...
   }

Expected behavior
Exception shouldn't be thrown.

[PWagner1]

@Smurf-IV Any ideas?

[ZXBITLES]

Well, I made a stupid workaround and its basically works:
default:
try
{
base.WndProc(ref m);
}
catch (Exception)
{ }
break;
I think, the reason is that some nodes are not available or not exist, so here we should write some kind if condition to check if it possible to call "base.WndProc(ref m);" or not, but I have no idea what to check...

By the way, for some reasons KryptonTreeView trying to collapse all the nodes when changing a palette, and when its done, then no exception is thrown.

[Smurf-IV]

@Smurf-IV Any ideas?

I have not seen this in the demo code

[Smurf-IV]

Well, I made a stupid workaround and its basically works: default: try { base.WndProc(ref m); } catch (Exception) { } break;

Where did you place this code ?

[ZXBITLES]

Where did you place this code ?

In "KryptonTreeView.cs" at "protected override void WndProc(ref Message m)".
By the way, I am creating KryptonManager dynamically on starting App before showing any forms and working with it to change a palette. So, KryptonManager does not lying on form. I don't think, that this is important, but must mention this.

[ZXBITLES]

Made a test - put KryptonManager to a form. The same result.
Besides of it, I see, that KryptonTreeView collapsing all the nodes on changing a palette. Could be that this can give an idea to find a reason.

[ZXBITLES]

Ok.
I think, that I got it!
Let me describe.
I created my own control which contains KryptonTreeView.
I am handling AfterSelect event for this KryptonTreeView.
The way to solve the problem is to check if e.Action equals to TreeViewAction.Unknown and exit a method in this case.
However, I do believe, that this is a bug and hope that my explanation can help to locate it.

"Bad" code:
Private Sub _TrvItems_AfterSelect(sender As Object, e As TreeViewEventArgs) Handles _TrvItems.AfterSelect
...
End Sub

"Good" code:
Private Sub _TrvItems_AfterSelect(sender As Object, e As TreeViewEventArgs) Handles _TrvItems.AfterSelect
If e.Action = TreeViewAction.Unknown Then Return
...
End Sub

[Smurf-IV]

Notes:
Would also fire when the following Sets happen:

• ItemStyle
• BackStyle
• BorderStyle
• PaletteChanged
• KryptonTreeView is created!
• and via the strange OCM_NOTIFY
• When selected item is deleted (Unknown will set then !)

Now should only fire when:

• When selected item is deleted (Unknown will set then !)
• When selected.
• Sometimes via the strange OCM_Notify

[Smurf-IV]

Coming to a PR soon....