Hi,

I am trying to capture the mouse events when the user clicks on the
desktop not the winform. I looked at the mouse_event function but MSDN
documentation says that it is suppressed in win NT/2000/XP. What I am
trying to do is to get print screen for a section on the desktop every
number of seconds. And I want the user to be able to select that
region.

Any help will be appreciated.

if you want to get a mouseclick event, just hook the mouse so it will tell
you whenever the mouse button is clicked
--
-iwdu15

That's true when you click on the form. But if you click outside the
form the even doesn't capture mouse events.


iwdu15 wrote:
> if you want to get a mouseclick event, just hook the mouse so it will tell
> you whenever the mouse button is clicked
> --
> -iwdu15

sorry for not being clear, i meant put a mouse hook on the formload event.
then you can receive every mouse click....ex:



Private Const HC_ACTION As Integer = 0
Private Const WH_MOUSE_LL As Integer = 14
Private Const WM_LBUTTONDOWN As Integer = &H201
Private Const WM_MOUSEWHEEL As Integer = &H20A

Private Declare Function SetWindowsHookEx Lib "user32" _
Alias "SetWindowsHookExA" ( _
ByVal idHook As Integer, _
ByVal lpfn As LowLevelMouseProcDelegate, _
ByVal hmod As Integer, _
ByVal dwThreadId As Integer) As Integer

Private Declare Function CallNextHookEx Lib "user32" ( _
ByVal hHook As Integer, _
ByVal nCode As Integer, _
ByVal wParam As Integer, _
ByVal lParam As MSLLHOOKSTRUCT) As Integer

Private Declare Function UnhookWindowsHookEx Lib "user32" ( _
ByVal hHook As Integer) As Integer

Private Function LowLevelMouseProc( _
ByVal nCode As Integer, _
ByVal wParam As Integer, _
ByVal lParam As MSLLHOOKSTRUCT) As Integer

If (nCode = HC_ACTION) Then

If wParam = WM_LBUTTONDOWN Then

''do something on left mouse click

End If

Return CallNextHookEx(hhkLowLevelMouse, _
nCode, wParam, lParam)

End If

End Function

Private Delegate Function LowLevelMouseProcDelegate( _
ByVal nCode As Integer, _
ByVal wParam As Integer, _
ByVal lParam As MSLLHOOKSTRUCT) As Integer


''set mouse hook
Public Sub DisableMouse()

'Set Mouse Hook
hhkLowLevelMouse = SetWindowsHookEx(WH_MOUSE_LL, _
AddressOf LowLevelMouseProc, _

Marshal.GetHINSTANCE(System.Reflection.Assembly.GetExecutingAssembly.GetModules()(0)).ToInt32, _
0)

End Sub


''release hook
Public Sub EnableMouse()

'Release Mouse Hook
UnhookWindowsHookEx(hhkLowLevelMouse)

End Sub


hope this helps

--
-iwdu15

Thanks alot. I think that almost did that trick except it is generating
an exception when reaching line:

Return CallNextHookEx(hhkLowLevelMouse, _
nCode, wParam, lParam)


That exception was about Stack. I will post the full exception message
when I get home.

Thanks again.


iwdu15 wrote:
> sorry for not being clear, i meant put a mouse hook on the formload event.
> then you can receive every mouse click....ex:
>
>
>
> Private Const HC_ACTION As Integer = 0
> Private Const WH_MOUSE_LL As Integer = 14
> Private Const WM_LBUTTONDOWN As Integer = &H201
> Private Const WM_MOUSEWHEEL As Integer = &H20A
>
> Private Declare Function SetWindowsHookEx Lib "user32" _
> Alias "SetWindowsHookExA" ( _
> ByVal idHook As Integer, _
> ByVal lpfn As LowLevelMouseProcDelegate, _
> ByVal hmod As Integer, _
> ByVal dwThreadId As Integer) As Integer
>
> Private Declare Function CallNextHookEx Lib "user32" ( _
> ByVal hHook As Integer, _
> ByVal nCode As Integer, _
> ByVal wParam As Integer, _
> ByVal lParam As MSLLHOOKSTRUCT) As Integer
>
> Private Declare Function UnhookWindowsHookEx Lib "user32" ( _
> ByVal hHook As Integer) As Integer
>
> Private Function LowLevelMouseProc( _
> ByVal nCode As Integer, _
> ByVal wParam As Integer, _
> ByVal lParam As MSLLHOOKSTRUCT) As Integer
>
> If (nCode = HC_ACTION) Then
>
> If wParam = WM_LBUTTONDOWN Then
>
> ''do something on left mouse click
>
> End If
>
> Return CallNextHookEx(hhkLowLevelMouse, _
> nCode, wParam, lParam)
>
> End If
>
> End Function
>
> Private Delegate Function LowLevelMouseProcDelegate( _
> ByVal nCode As Integer, _
> ByVal wParam As Integer, _
> ByVal lParam As MSLLHOOKSTRUCT) As Integer
>
>
> ''set mouse hook
> Public Sub DisableMouse()
>
> 'Set Mouse Hook
> hhkLowLevelMouse = SetWindowsHookEx(WH_MOUSE_LL, _
> AddressOf LowLevelMouseProc, _
>
> Marshal.GetHINSTANCE(System.Reflection.Assembly.GetExecutingAssembly.GetModules()(0)).ToInt32, _
> 0)
>
> End Sub
>
>
> ''release hook
> Public Sub EnableMouse()
>
> 'Release Mouse Hook
> UnhookWindowsHookEx(hhkLowLevelMouse)
>
> End Sub
>
>
> hope this helps
>
> --
> -iwdu15

I think I know what the problem is. I just searched the news group and
I found the following thread:

http://groups.google.ca/group/micros...bcdefa8cc811ca

It suggests replaceing the byval to byref for the fourth parameter in
the method. I will try it at home and I will let everybody know.

Thanks again

Ahmed wrote:
> Thanks alot. I think that almost did that trick except it is generating
> an exception when reaching line:
>
> Return CallNextHookEx(hhkLowLevelMouse, _
> nCode, wParam, lParam)
>
>
> That exception was about Stack. I will post the full exception message
> when I get home.
>
> Thanks again.
>
>
> iwdu15 wrote:
> > sorry for not being clear, i meant put a mouse hook on the formload event.
> > then you can receive every mouse click....ex:
> >
> >
> >
> > Private Const HC_ACTION As Integer = 0
> > Private Const WH_MOUSE_LL As Integer = 14
> > Private Const WM_LBUTTONDOWN As Integer = &H201
> > Private Const WM_MOUSEWHEEL As Integer = &H20A
> >
> > Private Declare Function SetWindowsHookEx Lib "user32" _
> > Alias "SetWindowsHookExA" ( _
> > ByVal idHook As Integer, _
> > ByVal lpfn As LowLevelMouseProcDelegate, _
> > ByVal hmod As Integer, _
> > ByVal dwThreadId As Integer) As Integer
> >
> > Private Declare Function CallNextHookEx Lib "user32" ( _
> > ByVal hHook As Integer, _
> > ByVal nCode As Integer, _
> > ByVal wParam As Integer, _
> > ByVal lParam As MSLLHOOKSTRUCT) As Integer
> >
> > Private Declare Function UnhookWindowsHookEx Lib "user32" ( _
> > ByVal hHook As Integer) As Integer
> >
> > Private Function LowLevelMouseProc( _
> > ByVal nCode As Integer, _
> > ByVal wParam As Integer, _
> > ByVal lParam As MSLLHOOKSTRUCT) As Integer
> >
> > If (nCode = HC_ACTION) Then
> >
> > If wParam = WM_LBUTTONDOWN Then
> >
> > ''do something on left mouse click
> >
> > End If
> >
> > Return CallNextHookEx(hhkLowLevelMouse, _
> > nCode, wParam, lParam)
> >
> > End If
> >
> > End Function
> >
> > Private Delegate Function LowLevelMouseProcDelegate( _
> > ByVal nCode As Integer, _
> > ByVal wParam As Integer, _
> > ByVal lParam As MSLLHOOKSTRUCT) As Integer
> >
> >
> > ''set mouse hook
> > Public Sub DisableMouse()
> >
> > 'Set Mouse Hook
> > hhkLowLevelMouse = SetWindowsHookEx(WH_MOUSE_LL, _
> > AddressOf LowLevelMouseProc, _
> >
> > Marshal.GetHINSTANCE(System.Reflection.Assembly.GetExecutingAssembly.GetModules()(0)).ToInt32, _
> > 0)
> >
> > End Sub
> >
> >
> > ''release hook
> > Public Sub EnableMouse()
> >
> > 'Release Mouse Hook
> > UnhookWindowsHookEx(hhkLowLevelMouse)
> >
> > End Sub
> >
> >
> > hope this helps
> >
> > --
> > -iwdu15

Thanks, its working fine.
Ahmed wrote:
> I think I know what the problem is. I just searched the news group and
> I found the following thread:
>
> http://groups.google.ca/group/micros...bcdefa8cc811ca
>
> It suggests replaceing the byval to byref for the fourth parameter in
> the method. I will try it at home and I will let everybody know.
>
> Thanks again
>
> Ahmed wrote:
> > Thanks alot. I think that almost did that trick except it is generating
> > an exception when reaching line:
> >
> > Return CallNextHookEx(hhkLowLevelMouse, _
> > nCode, wParam, lParam)
> >
> >
> > That exception was about Stack. I will post the full exception message
> > when I get home.
> >
> > Thanks again.
> >
> >
> > iwdu15 wrote:
> > > sorry for not being clear, i meant put a mouse hook on the formload event.
> > > then you can receive every mouse click....ex:
> > >
> > >
> > >
> > > Private Const HC_ACTION As Integer = 0
> > > Private Const WH_MOUSE_LL As Integer = 14
> > > Private Const WM_LBUTTONDOWN As Integer = &H201
> > > Private Const WM_MOUSEWHEEL As Integer = &H20A
> > >
> > > Private Declare Function SetWindowsHookEx Lib "user32" _
> > > Alias "SetWindowsHookExA" ( _
> > > ByVal idHook As Integer, _
> > > ByVal lpfn As LowLevelMouseProcDelegate, _
> > > ByVal hmod As Integer, _
> > > ByVal dwThreadId As Integer) As Integer
> > >
> > > Private Declare Function CallNextHookEx Lib "user32" ( _
> > > ByVal hHook As Integer, _
> > > ByVal nCode As Integer, _
> > > ByVal wParam As Integer, _
> > > ByVal lParam As MSLLHOOKSTRUCT) As Integer
> > >
> > > Private Declare Function UnhookWindowsHookEx Lib "user32" ( _
> > > ByVal hHook As Integer) As Integer
> > >
> > > Private Function LowLevelMouseProc( _
> > > ByVal nCode As Integer, _
> > > ByVal wParam As Integer, _
> > > ByVal lParam As MSLLHOOKSTRUCT) As Integer
> > >
> > > If (nCode = HC_ACTION) Then
> > >
> > > If wParam = WM_LBUTTONDOWN Then
> > >
> > > ''do something on left mouse click
> > >
> > > End If
> > >
> > > Return CallNextHookEx(hhkLowLevelMouse, _
> > > nCode, wParam, lParam)
> > >
> > > End If
> > >
> > > End Function
> > >
> > > Private Delegate Function LowLevelMouseProcDelegate( _
> > > ByVal nCode As Integer, _
> > > ByVal wParam As Integer, _
> > > ByVal lParam As MSLLHOOKSTRUCT) As Integer
> > >
> > >
> > > ''set mouse hook
> > > Public Sub DisableMouse()
> > >
> > > 'Set Mouse Hook
> > > hhkLowLevelMouse = SetWindowsHookEx(WH_MOUSE_LL, _
> > > AddressOf LowLevelMouseProc, _
> > >
> > > Marshal.GetHINSTANCE(System.Reflection.Assembly.GetExecutingAssembly.GetModules()(0)).ToInt32, _
> > > 0)
> > >
> > > End Sub
> > >
> > >
> > > ''release hook
> > > Public Sub EnableMouse()
> > >
> > > 'Release Mouse Hook
> > > UnhookWindowsHookEx(hhkLowLevelMouse)
> > >
> > > End Sub
> > >
> > >
> > > hope this helps
> > >
> > > --
> > > -iwdu15