Call .DLL then callback

[=?Utf-8?B?Sm9lbWFuYw==?=]

Hi,
I'm trying to figure out the Callback method. I have a .dll that I call from
a sub in my unmanaged code/calling program. That works just fine. But I'd
like to have the .dll finish doing it's thing before returning to my calling
program. Right now, with the code I've been testing with, the calling program
goes to the .dll and then returns back to the calling program without letting
the .dll do it's thing. Just having a hard time figuring out the callback
routine. If someone could lead me to a good example, that would be great.
Thanks!

[Anil Gupte/iCinema.com]

Re: Call .DLL then callback

I am not real familiar with it, but I think DoEvents() might be your answer.

You could just put your program in some kind of loop controlled by a timer
and wait till the DLL sets some variable signifying it is done.

--
Anil Gupte

https://www.keeninc.net

https://www.icinema.com

https://www.wizo.tv

"Joemanc" <jmanci@cl-law.com.donotsp amwrote in message
news:1FA36E4D-0453-4595-A6C5-C29C37B85241@mi crosoft.com...

Hi,
I'm trying to figure out the Callback method. I have a .dll that I call
from
a sub in my unmanaged code/calling program. That works just fine. But I'd
like to have the .dll finish doing it's thing before returning to my
calling
program. Right now, with the code I've been testing with, the calling
program
goes to the .dll and then returns back to the calling program without
letting
the .dll do it's thing. Just having a hard time figuring out the callback
routine. If someone could lead me to a good example, that would be great.
Thanks!

[Tom Shelton]

Re: Call .DLL then callback

On 2008-06-10, Joemanc <jmanci@cl-law.com.donotsp amwrote:

Hi,
I'm trying to figure out the Callback method. I have a .dll that I call from
a sub in my unmanaged code/calling program. That works just fine. But I'd
like to have the .dll finish doing it's thing before returning to my calling
program. Right now, with the code I've been testing with, the calling program
goes to the .dll and then returns back to the calling program without letting
the .dll do it's thing. Just having a hard time figuring out the callback
routine. If someone could lead me to a good example, that would be great.
Thanks!

Ok... Here you go a simple example that calls the EnumWindows api:

Option Strict On
Option Explicit On
Option Infer Off

Imports System
Imports System.Text
Imports System.Runtime. InteropServices

Module Module1

' callback delegate
Private Delegate Function EnumWindowCallb ackDelegate(ByV al hWnd As IntPtr, ByVal lParam As IntPtr) As Boolean

' EnumWindows declare
Private Declare Function EnumWindows Lib "user32" (ByVal lpEnumFunc As EnumWindowCallb ackDelegate, ByVal lParam As IntPtr) As Boolean

Private Declare Auto Function GetWindowTextLe ngth Lib "user32" (ByVal hWnd As IntPtr) As Integer
Private Declare Auto Function GetWindowText Lib "user32" (ByVal hWnd As IntPtr, ByVal lpString As StringBuilder, ByVal nMaxCount As Integer) As Integer

Sub Main()
Dim cb As New EnumWindowCallb ackDelegate(Add ressOf EnumWindowsCall backFunction)
EnumWindows(cb, IntPtr.Zero)
End Sub

Private Function EnumWindowsCall backFunction(By Val hWnd As IntPtr, ByVal lParam As IntPtr) As Boolean
Dim bufferLength As Integer = GetWindowTextLe ngth(hWnd)
If (bufferLength 0) Then
Dim buffer As New StringBuilder(b ufferLength + 1)
If GetWindowText(h Wnd, buffer, buffer.Capacity ) 0 Then
Console.WriteLi ne(buffer.ToStr ing())
End If
End If
Return True
End Function
End Module

Now, the trick here is that the EnumWindows api takes a function pointer - so,
we declare a delegate type with the same signature - and that is what we pass.
A delegate is, after alll, a object oriented function pointer :)

--
Tom Shelton

[=?Utf-8?B?Sm9lbWFuYw==?=]

Re: Call .DLL then callback

Tom,
I had found a similar sample online, but yours does not work either. But I
feel as if I'm close.

This is the code I'm now using in my calling program:

Sub Outlook_Startup
Dim cb As New EnumWindowCallb ackDelegate(Add ressOf MyProject.Main)
EnumWindows(cb, IntPtr.Zero)
Call ReturnContact 'code to process after the .dll is finished running
End Sub

This is the code called in the .dll

Public Function Main(ByVal hwnd As Integer, ByVal lParam As Integer)
As Boolean

objOutlook = New Outlook.Applica tion()
ns = objOutlook.Sess ion
Dim MyContactFolder s As Outlook.MAPIFol der =
(ns.GetDefaultF older(Outlook.O lDefaultFolders .olFolderContac ts))

Dim MyDefaultProfil e As RegistryKey
Dim MyKey As String

Try
MyDefaultProfil e =
Registry.Curren tUser.OpenSubKe y("Software\Mic rosoft\Windows
NT\CurrentVersi on\Windows Messaging Subsystem\Profi les", False)
MyKey = MyDefaultProfil e.GetValue("Def aultProfile", "")
ns.Logon("Outlo ok", , False, False)
Call GetAllContactFo lders()

MyContacts.Show ()
MyContacts.Brin gToFront()

Catch ex As Exception
MsgBox(Err.Desc ription)
End Try

End Function

The behavior I'm getting is different from the code you sent me that I
tested. The code execution runs through the .dll and then returns to the
calling program and then tries to run that 'ReturnCode' sub. It never stops
to allow the .dll to do it's job.

I was able to call the Main sub in the .dll using this code:

Dim caller As New AsyncMethodCall er(AddressOf MyProject.Main)
threadId = Thread.CurrentT hread.ManagedTh readId()
caller.Invoke(3 000, threadId)

This code was giving full control to the .dll. The only problem is, I'm not
able to return back to my .dll.
Do you have any ideas on what I may be doing wrong? Thanks!

"Tom Shelton" wrote:

On 2008-06-10, Joemanc <jmanci@cl-law.com.donotsp amwrote:

Hi,
I'm trying to figure out the Callback method. I have a .dll that I call from
a sub in my unmanaged code/calling program. That works just fine. But I'd
like to have the .dll finish doing it's thing before returning to my calling
program. Right now, with the code I've been testing with, the calling program
goes to the .dll and then returns back to the calling program without letting
the .dll do it's thing. Just having a hard time figuring out the callback
routine. If someone could lead me to a good example, that would be great.
Thanks!

>
Ok... Here you go a simple example that calls the EnumWindows api:
>
Option Strict On
Option Explicit On
Option Infer Off
>
Imports System
Imports System.Text
Imports System.Runtime. InteropServices
>
Module Module1
>
' callback delegate
Private Delegate Function EnumWindowCallb ackDelegate(ByV al hWnd As IntPtr, ByVal lParam As IntPtr) As Boolean
>
' EnumWindows declare
Private Declare Function EnumWindows Lib "user32" (ByVal lpEnumFunc As EnumWindowCallb ackDelegate, ByVal lParam As IntPtr) As Boolean
>
Private Declare Auto Function GetWindowTextLe ngth Lib "user32" (ByVal hWnd As IntPtr) As Integer
Private Declare Auto Function GetWindowText Lib "user32" (ByVal hWnd As IntPtr, ByVal lpString As StringBuilder, ByVal nMaxCount As Integer) As Integer
>
Sub Main()
Dim cb As New EnumWindowCallb ackDelegate(Add ressOf EnumWindowsCall backFunction)
EnumWindows(cb, IntPtr.Zero)
End Sub
>
Private Function EnumWindowsCall backFunction(By Val hWnd As IntPtr, ByVal lParam As IntPtr) As Boolean
Dim bufferLength As Integer = GetWindowTextLe ngth(hWnd)
If (bufferLength 0) Then
Dim buffer As New StringBuilder(b ufferLength + 1)
If GetWindowText(h Wnd, buffer, buffer.Capacity ) 0 Then
Console.WriteLi ne(buffer.ToStr ing())
End If
End If
Return True
End Function
End Module
>
Now, the trick here is that the EnumWindows api takes a function pointer - so,
we declare a delegate type with the same signature - and that is what we pass.
A delegate is, after alll, a object oriented function pointer :)
>
--
Tom Shelton
>

[=?Utf-8?B?Sm9lbWFuYw==?=]

Re: Call .DLL then callback

ok, I think I got it! I'm displaying my forms in the .dll with .show
instead of .showdialog. I changed the calls to .showdialog and that seems to
be doing the trick. The code was just showing the form and then continuing
on. Looks like showdialog is helping to keep the code in the .dll. Very
tricky stuff!

"Tom Shelton" wrote:

On 2008-06-10, Joemanc <jmanci@cl-law.com.donotsp amwrote:

Hi,
I'm trying to figure out the Callback method. I have a .dll that I call from
a sub in my unmanaged code/calling program. That works just fine. But I'd
like to have the .dll finish doing it's thing before returning to my calling
program. Right now, with the code I've been testing with, the calling program
goes to the .dll and then returns back to the calling program without letting
the .dll do it's thing. Just having a hard time figuring out the callback
routine. If someone could lead me to a good example, that would be great.
Thanks!

>
Ok... Here you go a simple example that calls the EnumWindows api:
>
Option Strict On
Option Explicit On
Option Infer Off
>
Imports System
Imports System.Text
Imports System.Runtime. InteropServices
>
Module Module1
>
' callback delegate
Private Delegate Function EnumWindowCallb ackDelegate(ByV al hWnd As IntPtr, ByVal lParam As IntPtr) As Boolean
>
' EnumWindows declare
Private Declare Function EnumWindows Lib "user32" (ByVal lpEnumFunc As EnumWindowCallb ackDelegate, ByVal lParam As IntPtr) As Boolean
>
Private Declare Auto Function GetWindowTextLe ngth Lib "user32" (ByVal hWnd As IntPtr) As Integer
Private Declare Auto Function GetWindowText Lib "user32" (ByVal hWnd As IntPtr, ByVal lpString As StringBuilder, ByVal nMaxCount As Integer) As Integer
>
Sub Main()
Dim cb As New EnumWindowCallb ackDelegate(Add ressOf EnumWindowsCall backFunction)
EnumWindows(cb, IntPtr.Zero)
End Sub
>
Private Function EnumWindowsCall backFunction(By Val hWnd As IntPtr, ByVal lParam As IntPtr) As Boolean
Dim bufferLength As Integer = GetWindowTextLe ngth(hWnd)
If (bufferLength 0) Then
Dim buffer As New StringBuilder(b ufferLength + 1)
If GetWindowText(h Wnd, buffer, buffer.Capacity ) 0 Then
Console.WriteLi ne(buffer.ToStr ing())
End If
End If
Return True
End Function
End Module
>
Now, the trick here is that the EnumWindows api takes a function pointer - so,
we declare a delegate type with the same signature - and that is what we pass.
A delegate is, after alll, a object oriented function pointer :)
>
--
Tom Shelton
>

[Michael Leithold, WWK]

Re: Call .DLL then callback

On 10 Jun., 18:05, Joemanc <jma...@cl-law.com.donotsp amwrote:

I'm trying to figure out the Callback method. I have a .dll that I call from
a sub in my unmanaged code/calling program. That works just fine. But I'd
like to have the .dll finish doing it's thing before returning to my calling
program. Right now, with the code I've been testing with, the calling program
goes to the .dll and then returns back to the calling program without letting
the .dll do it's thing. Just having a hard time figuring out the callback
routine. If someone could lead me to a good example, that would be great.

Maybe you could use an event? Raise an event when you dll has
finished. Then proceed in your calling program.

Michael

[=?Utf-8?B?Sm9lbWFuYw==?=]

Re: Call .DLL then callback

I actually ended up going all the way back to my original code that I had
posted below, with the caller.invoke method.
Between that and changing my calls in the .dll for the user forms from .Show
to .ShowDialog, that is working!
Thanks for all of your help and suggestions. Hopefully this thread can help
out someone with a similar problem in the future.

"Michael Leithold, WWK" wrote:

On 10 Jun., 18:05, Joemanc <jma...@cl-law.com.donotsp amwrote:

I'm trying to figure out the Callback method. I have a .dll that I call from
a sub in my unmanaged code/calling program. That works just fine. But I'd
like to have the .dll finish doing it's thing before returning to my calling
program. Right now, with the code I've been testing with, the calling program
goes to the .dll and then returns back to the calling program without letting
the .dll do it's thing. Just having a hard time figuring out the callback
routine. If someone could lead me to a good example, that would be great.

>
Maybe you could use an event? Raise an event when you dll has
finished. Then proceed in your calling program.
>
Michael
>
>