"Lance" <Lance@discussions.microsoft.com> wrote in message
news:CF88A7CA-5641-4479-A87B-65ED115ED7B7@microsoft.com...
>I need to have a form load whenever a new serial port is added to the
>system.
>
> I've created an EventWatcher to perform this and the event is triggered as
> expected. However, the form that is loaded from within the event is
> frozen.
> The mouse is in the hourglass, the form cannot be clicked, moved, closed,
> activated, and does not properly display itself. I've checked to see if
> it
> is a problem with the form, however even if the form has no controls/code
> other than the windows required code, it still behaves in this fashion.
>
> Can anyone give me some insight as to why this is happening, or a possible
> alternative method.
>
> Code snippet:
>
> Private Class PortMonitor
> Private w As ManagementEventWatcher = Nothing
>
> Public Sub Start()
> Dim q As WqlEventQuery = New WqlEventQuery
> q.EventClassName = "__InstanceCreationEvent"
> q.WithinInterval = New TimeSpan(0, 0, 3)
> q.Condition = "TargetInstance ISA 'Win32_SerialPort'"
> w = New ManagementEventWatcher(q)
> AddHandler w.EventArrived, New
> EventArrivedEventHandler(AddressOf Me.OnPortArrived)
> w.Start()
> End Sub
>
> Public Sub [Stop]()
> RemoveHandler w.EventArrived, New
> EventArrivedEventHandler(AddressOf Me.OnPortArrived)
> w.Stop()
> w.Dispose()
> End Sub
>
> Protected Sub OnPortArrived(ByVal sender As Object, ByVal e As
> EventArrivedEventArgs)
> Dim f As New Form1
> f.Show() ' Form is locked up!
> End Sub
> End Class
>
> Thanks
>

"Willy Denoyette [MVP]" wrote:

> The OnPortArrived eventhandler is running on a threadpool thread, NOT on the
> UI thread. Threadpool threads have no message pump and shold not be used to
> show windows UI elements!
> What you should do is delegate the OnPortArrived event handling on the UI
> thread, check the "MethodInvoker" method in MSDN.
>
> Willy.
>
>
> "Lance" <Lance@discussions.microsoft.com> wrote in message
> news:CF88A7CA-5641-4479-A87B-65ED115ED7B7@microsoft.com...
> >I need to have a form load whenever a new serial port is added to the
> >system.
> >
> > I've created an EventWatcher to perform this and the event is triggered as
> > expected. However, the form that is loaded from within the event is
> > frozen.
> > The mouse is in the hourglass, the form cannot be clicked, moved, closed,
> > activated, and does not properly display itself. I've checked to see if
> > it
> > is a problem with the form, however even if the form has no controls/code
> > other than the windows required code, it still behaves in this fashion.
> >
> > Can anyone give me some insight as to why this is happening, or a possible
> > alternative method.
> >
> > Code snippet:
> >
> > Private Class PortMonitor
> > Private w As ManagementEventWatcher = Nothing
> >
> > Public Sub Start()
> > Dim q As WqlEventQuery = New WqlEventQuery
> > q.EventClassName = "__InstanceCreationEvent"
> > q.WithinInterval = New TimeSpan(0, 0, 3)
> > q.Condition = "TargetInstance ISA 'Win32_SerialPort'"
> > w = New ManagementEventWatcher(q)
> > AddHandler w.EventArrived, New
> > EventArrivedEventHandler(AddressOf Me.OnPortArrived)
> > w.Start()
> > End Sub
> >
> > Public Sub [Stop]()
> > RemoveHandler w.EventArrived, New
> > EventArrivedEventHandler(AddressOf Me.OnPortArrived)
> > w.Stop()
> > w.Dispose()
> > End Sub
> >
> > Protected Sub OnPortArrived(ByVal sender As Object, ByVal e As
> > EventArrivedEventArgs)
> > Dim f As New Form1
> > f.Show() ' Form is locked up!
> > End Sub
> > End Class
> >
> > Thanks
> >
>
>