Altramagnus
Fri May 13 05:12:52 CDT 2005
OK thanks.
I think CreateHandle works.
Sorry it was my mistake.
"Armin Zingler" <az.nospam@freenet.de> wrote in message
news:u$WsFV5VFHA.1796@TK2MSFTNGP15.phx.gbl...
> "Altramagnus" <altramagnus@hotmail.com> schrieb
>> "Armin Zingler" <az.nospam@freenet.de> wrote in message
>> news:%23cdXxAwVFHA.1152@tk2msftngp13.phx.gbl...
>>> "Altramagnus" <altramagnus@hotmail.com> schrieb
>>>>I have a form first created my the main thread.
>>>> I have another thread monitoring the IO.
>>>> Upon receiving certain message, I want to show/unhide the form.
>>>>
>>>> When the form is first created ( handle is not created until it
>>>> is first shown ).
>>>> How do my IO thread invoke the form to show? ( in order to invoke
>>>> the form, the form handle must be created )
>>>
>>> 2 suggestions: You could call CreateHandle in the main thread after
>>> the form has been created. Or, use an empty dummy form created in
>>> the main thread used by (Begin)Invoke in the 2nd thread. The target
>>> procedure in the main thread then shows the actual form.
>>>
>>
>> The first method would not work because,
>> even you explictly call CreateHandle, the handle would still not be
>> created until the form is first visible.
>> In other words, if the form is not visible, createHandle does
>> nothing.
>
> Sure? I tried it and it worked. In a new project, add a button and this
> code
> (sorry, VB.NET, but you'll see the point):
>
> Shared f As Form1
> Private Sub Button1_Click(ByVal sender As System.Object, _
> ByVal e As System.EventArgs) Handles Button1.Click
>
> f = New Form1
> f.CreateHandle()
> Dim t As New Threading.Thread(AddressOf a)
> t.Start()
> End Sub
> Private Delegate Sub d()
> Private Shared Sub a()
> f.BeginInvoke(New d(AddressOf b))
> End Sub
> Private Shared Sub b()
>
> End Sub
>
> Exception without createhandle, no exception with createhandle.
>
>
>> The second method works if i have a existing form that is already
>> shown. It will still be a problem if I have no existing form.
>
> Yes, that's why you could add one, but you don't have to show it.
>
>
> Armin
>