Capturing mouse events (Mouse up and down on the desktop)

6 Jun 2006 3:48 PM

Ahmed

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.

6 Jun 2006 8:01 PM

iwdu15

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

--
-iwdu15

6 Jun 2006 11:30 PM

Ahmed

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:
Show quoteHide quote

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

7 Jun 2006 12:51 AM

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

7 Jun 2006 4:28 PM

Ahmed

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:
Show quoteHide quote

> 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

7 Jun 2006 4:33 PM

Ahmed

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/microsoft.public.dotnet.languages.vb/browse_thread/thread/a33d0ceeb075a1dd/91bcdefa8cc811ca?q=CallNextHookEx+stack&rnum=1#91bcdefa8cc811ca

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:
Show quoteHide quote

> 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

8 Jun 2006 5:52 AM

Ahmed

Thanks, its working fine.
Ahmed wrote:
Show quoteHide quote

> 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/microsoft.public.dotnet.languages.vb/browse_thread/thread/a33d0ceeb075a1dd/91bcdefa8cc811ca?q=CallNextHookEx+stack&rnum=1#91bcdefa8cc811ca
>
> 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