ComboBox drop-down window closing/hidden

[- HAL9000]

I am trying to get an event when the drop-down Combo Box goes away /
reverts back to showing a single item.

For example, clicking the box's down arrow, to remove the drop-down
window, doesn't seem to generate any event. Not even a mouse event.
That seems a little odd.

Besides not finding a public event method, I can't seem to find a
protected method to over-ride either.

I am guessing I need to look for a message in ComboBox's WndProc().
But I don't know which message is the one I'm looking for.

Any ideas ?

Thanks...

[kimiraikkonen]

Re: ComboBox drop-down window closing/hidden

On Mar 21, 10:00 am, - HAL9000 <gu...@mail.org wrote:

I am trying to get an event when the drop-down Combo Box goes away /
reverts back to showing a single item.
>
For example, clicking the box's down arrow, to remove the drop-down
window, doesn't seem to generate any event. Not even a mouse event.
That seems a little odd.
>
Besides not finding a public event method, I can't seem to find a
protected method to over-ride either.
>
I am guessing I need to look for a message in ComboBox's WndProc().
But I don't know which message is the one I'm looking for.
>
Any ideas ?
>
Thanks...

DropDownClosed event of combobox must be what you're looking for.

[- HAL9000]

Re: ComboBox drop-down window closing/hidden

On Fri, 21 Mar 2008 02:32:01 -0700 (PDT), kimiraikkonen
<kimiraikkonen8 5@gmail.comwrot e:

>On Mar 21, 10:00 am, - HAL9000 <gu...@mail.org wrote:

>I am trying to get an event when the drop-down Combo Box goes away /
>reverts back to showing a single item.
>>
>For example, clicking the box's down arrow, to remove the drop-down
>window, doesn't seem to generate any event. Not even a mouse event.
>That seems a little odd.
>>
>Besides not finding a public event method, I can't seem to find a
>protected method to over-ride either.
>>
>I am guessing I need to look for a message in ComboBox's WndProc().
>But I don't know which message is the one I'm looking for.
>>
>Any ideas ?
>>
>Thanks...

>
>DropDownClos ed event of combobox must be what you're looking for.

Ahh, I see they added DropDownClosed( ) event for .net version 2. I
have to use version 1, so I can't use that.

That tip did lead me to the information I needed though (eg
CBN_CLOSEUP message):

http://groups.google.com/group/microsoft.public.dotnet.languages.vb/msg/b174deef8895fc73

Changed that around a little to:

Protected Overrides Sub WndProc(ByRef m As
System.Windows. Forms.Message)
'WM_USER As Integer = &H400
'OCM__BASE As Integer = WM_USER + &H1C00
'WM_COMMAND As Integer = &H111
'OCM_COMMAND As Integer = OCM__BASE + WM_COMMAND
If m.Msg = (&H400 + &H111 + &H1C00) Then
Debug.WriteLine ("WndProc Msg = " & Hex(m.Msg) & "h, LParam =
" & Hex(m.LParam.To Int32) & "h, WParam = " & Hex(m.WParam.To Int32) &
"h, HWnd = " & Hex(m.HWnd.ToIn t32) & "h")
If (m.WParam.ToInt 32 And &HF0000) = &H80000 Then
Debug.WriteLine ("drop down window close message")
OnDropDownWindo wClose(System.E ventArgs.Empty)
End If
End If
MyBase.WndProc( m)
End Sub

Protected Overridable Sub OnDropDownWindo wClose(ByVal e As
System.EventArg s)
RaiseEvent DropDownWindowC lose(Me, e)
End Sub

Public Event DropDownWindowC lose As EventHandler

[kimiraikkonen]

Re: ComboBox drop-down window closing/hidden

On Mar 21, 11:21 pm, - HAL9000 <gu...@mail.org wrote:

On Fri, 21 Mar 2008 02:32:01 -0700 (PDT), kimiraikkonen
>
>
>
>
>
<kimiraikkone.. .@gmail.comwrot e:

On Mar 21, 10:00 am, - HAL9000 <gu...@mail.org wrote:

I am trying to get an event when the drop-down Combo Box goes away /
reverts back to showing a single item.

>

For example, clicking the box's down arrow, to remove the drop-down
window, doesn't seem to generate any event.  Not even a mouse event.
That seems a little odd.

>

Besides not finding a public event method, I can't seem to find a
protected method to over-ride either.

>

I am guessing I need to look for a message in ComboBox's WndProc().
But I don't know which message is the one I'm looking for.

>

Any ideas ?

>

Thanks...

>

DropDownClosed event of combobox must be what you're looking for.

>
Ahh, I see they added DropDownClosed( ) event for .net version 2.  I
have to use version 1, so I can't use that.
>
That tip did lead me to the information I needed though (eg
CBN_CLOSEUP message):
>
http://groups.google.com/group/micro...languages.vb/m...
>
Changed that around a little to:
>
   Protected Overrides Sub WndProc(ByRef m As
System.Windows. Forms.Message)
      'WM_USER As Integer = &H400
      'OCM__BASE As Integer = WM_USER + &H1C00
      'WM_COMMAND As Integer = &H111
      'OCM_COMMAND As Integer = OCM__BASE + WM_COMMAND
      If m.Msg = (&H400 + &H111 + &H1C00) Then
         Debug.WriteLine ("WndProc Msg = " & Hex(m.Msg) & "h, LParam =
" & Hex(m.LParam.To Int32) & "h, WParam = " & Hex(m.WParam.To Int32) &
"h, HWnd = " & Hex(m.HWnd.ToIn t32) & "h")
         If (m.WParam.ToInt 32 And &HF0000) = &H80000 Then
            Debug.WriteLine ("drop down window close message")
            OnDropDownWindo wClose(System.E ventArgs.Empty)
         End If
      End If
      MyBase.WndProc( m)
   End Sub
>
   Protected Overridable Sub OnDropDownWindo wClose(ByVal e As
System.EventArg s)
      RaiseEvent DropDownWindowC lose(Me, e)
   End Sub
>
   Public Event DropDownWindowC lose As EventHandler- Hide quoted text -
>
- Show quoted text -

I think it's your time to jump .net 2.0 at least. DropDownClosed is
well-wrapped event rather than writing low-level Win32 API calls as
you described above.