Why is my event handler firing two times? - vb.net

Question

I have a bunch of panels that I am adding to a single parent panel and I want to add event listeners to all of the panels but not until after they have all been added to the parent (becuase I don't want the event listeners firing each time a new panel gets added). So I am using the following code:
Dim temp_object As question_bar = Nothing
For Each q As Object In review_holder.Controls
If TypeOf q Is question_bar Then
temp_object = q
AddHandler temp_object.Resize, AddressOf temp_object.resize_me
End If
Next
For Each q As Object In review_holder.Controls
If TypeOf q Is question_bar Then
temp_object = q
temp_object.resize_me()
End If
Next
But I noticed that the resize_me() subroutine is getting fired twice for each control. I only want it to fire once. So I traced it out using this code
MsgBox((New System.Diagnostics.StackTrace).GetFrame(1).GetMethod.Name)
and I see that each time it gets called the calling methods are both this subroutine and _Lambda$_365. What the heck is that? How do I find out where that is coming from?
BTW, this is a winforms app using VS2012.
EDIT ------------------------------------------------------------------------
Public Sub resize_me()
MsgBox((New System.Diagnostics.StackTrace).GetFrame(1).GetMethod.Name)
If Me.minimized = True Then
Me.Height = 0
Exit Sub
End If
number_panel.Width = my_parent.number_width
number_text.Width = my_parent.number_width
number_separator.Left = number_panel.Right
question_panel.Left = number_separator.Right
question_panel.Width = question_panel.Parent.Width * initial_question_width + (question_padding * 2)
End Sub

Answer 1

Well changing size properties when you are inside a resize event could explain why your code is recalled again a second time. Usually I try to avoid this kind of situations but this is not always possible. In these cases then a global variable that acts as a flag to block the reentry could save the day
Dim insideResize As Boolean
Public Sub resize_me()
if insideResize = True Then
Exit Sub
End if
insideResize = True
Try
If Me.minimized = True Then
Me.Height = 0
Exit Sub
End If
number_panel.Width = my_parent.number_width
number_text.Width = my_parent.number_width
number_separator.Left = number_panel.Right
question_panel.Left = number_separator.Right
question_panel.Width = question_panel.Parent.Width * initial_question_width + (question_padding * 2)
Finally
insideResize = False
End Try
End Sub
To stay on the safe side with this patterns remember to always use a Try/Finally block to be sure that when you exit from the Resize event the global flag is correctly set back to false.