#25 Group selection / LayerUITypeEditor exception

[Jeffrey A. Hare]

I've noticed in my application that if I have the
property editor up and select multiple items using the
mouse-down selection rectangle, that this exception
gets thrown.

If I use shift-LeftMouse to select multiple items, I
don't get this exception.

I replaced the Cobalt NetronGraphLib with the latest
CVS version of Netron_F11 and see the same result in
the Cobalt application. Also the NetronQuickStart app
can reproduce the problem.

LayerUITypeEditor.cs: line 65
//fetching the color of the layer requires a long deep
access...
args.Graphics.FillRectangle(new SolidBrush
(((Entity)((PropertyBag)
args.Context.Instance).Owner).Layer.LayerColor), r);

System.InvalidCastException was unhandled by user code
Message="Unable to cast object of type
'System.Object[]' to type 'Netron.GraphLib.PropertyBag'."
Source="NetronGraphLib"
StackTrace:
at
Netron.GraphLib.LayerUITypeEditor.PaintValue(PaintValueEventArgs
args) in
C:\ATM_MAIN\NetronSourceForge\Netron_F11\NetronGraphLibrary\UI\Layers\LayerUITypeEditor.cs:line
65
at
System.Windows.Forms.PropertyGridInternal.GridEntry.PaintValue(Object
val, Graphics g, Rectangle rect, Rectangle clipRect,
PaintValueFlags paintFlags)
at
System.Windows.Forms.PropertyGridInternal.PropertyGridView.DrawValue(Graphics
g, Rectangle rect, Rectangle clipRect, GridEntry
gridEntry, Object value, Boolean drawSelected, Boolean
checkShouldSerialize, Boolean fetchValue, Boolean
paintInPlace)
at
System.Windows.Forms.PropertyGridInternal.PropertyGridView.DrawValueEntry(Graphics
g, Rectangle rect, Rectangle clipRect, GridEntry
gridEntry, Object value, Boolean fetchValue)
at
System.Windows.Forms.PropertyGridInternal.PropertyGridView.DrawValueEntry(Graphics
g, Int32 row, Rectangle& clipRect)

[Jeffrey A. Hare]

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I should have noted that this exception is caught and
ignored, so doesn't show up outside the debugger. I guess
this lowers its priority.

[Mark Johnson, Berlin Germany]

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Noted for further consideration, other options requested.

[Mark Johnson, Berlin Germany]

Logged In: YES
user_id=1246985

After working this for three hous, I suddenly wonder why
this running at all.

So the Question should be asked : should this return with
no action when more than on Object is selected.

Fact is :
Under normal use 'args.Context.Instance' is a
- PropertyDescriptorGridEntry
with mouse-down selection it is a
- MultiPropertyDescriptorGridEntry
(this fails since 'PropertyDescriptorGridEntry' is
expected)

with shift-LeftMouse it
- does not seem to be called at all.

I don't know where this setting is.
I think the best thing would be to return if the casting
fails.