---- Reported by albright@wesay.org 2007-02-01 06:42:40 MST ----

Description of Problem:
When ListBox.SelectedIndex is assigned -1 to clear selection, causes System
ArgumentException to be thrown.

Steps to reproduce the problem:
1. Create a ListBox.
2. Assign -1 in SelectedIndex
3. Kaboom

Actual Results:
System.ArgumentException throws '-1' is not a valid value

Stack is:
at System.Windows.Forms.ScrollBar.set_Value (Int32 value)
at (wrapper remoting-invoke-with-check)
System.Windows.Forms.ScrollBar:set_Value (int)
at System.Windows.Forms.ListBox.UpdateTopItem ()
at System.Windows.Forms.ListBox.set_SelectedIndex (Int32 value)

Expected Results:
Unselect ListBox

How often does this happen? 


Additional Information:



---- Additional Comments From georgegiolfan@yahoo.com 2007-02-07 08:59:40 MST ----

If I understand correctly, top_index is the index of the first 
visible item. If this is the case, setting it to -1 does not make 
sense. I propose changing ListBox.SelectedIndex so that
    				if (value < top_index)
    				{
    					top_index = value;
    					UpdateTopItem ();
    				} else {
    					int rows = items_area.Height 
/ ItemHeight;
    					if (value >= (top_index + 
rows))
    					{
    						top_index = value - 
rows + 1;
    						UpdateTopItem ();
    					}
    				}
is executed only if value is not -1.




---- Additional Comments From georgegiolfan@yahoo.com 2007-03-10 11:25:05 MST ----

Created an attachment (id=171377)
Proposed patch




---- Additional Comments From mkestner@ximian.com 2007-03-27 11:46:41 MST ----

revision 75022.

Imported an attachment (id=171377)

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