Hi all.
I'm primarly a C++ developer but I've been trying to complete development on
a C# application with the following basic requirements:
- The app runs in the background is initially hidden from the user,
including the Windows Taskbar.
- The app needs to receive a registered Windows message
- The app needs to "register" its window handle with an unmanaged C++ dll so
that a WM_USER message can be sent back to the C# app's WndProc
- The app needs to display itself when receiving the WM_USER message, and
hide itself after being acted upon by the user.
I ran into some problems along the way and wondered if anyone could provide
some feedback or comments. Especially since I told my project guy this
should be trivial to do in C#, and now I'm wondering if I made the correct
decision. I'm not looking good at this point.
1) In order to hide the app from the Taskbar, the main form's ShowInTaskbar
property would be set to "false", easy right? That action, however, (using
SPY++)removes the WS_APPLICATION style bit and prevents the application from
receiving any registered Windows messages.
2) I initially call a C#-to-C++ wrapper function to give my ".Handle" to the
unmanaged dll. This works for the first time, but when I set the main form's
Visible property to false and minimize the form, "Handle" gets a new value.
Is there some other "handle" I should be using? I work around this by
"re-registering" with the unmanaged dll after minimizing but there have been
a couple of occasions where a zero has been logged. Using FindWindow() in
the unmanaged dll would be acceptable, is there a way to "register a unique
window class"? The window titlebar includes message specific data so the
title changes.
3) I have seen several instances where the main window was shown (Visible =
true), but with no controls on it. Using SPY++, I see the main window listed
with no child controls, and a "WindowsFormsParkingWindow" which contains all
the children for this form. The data on the controls is correct, but it's as
if they are just not on the right form.
4) I also intended for a Windows Service to start the application, which
works, but the application does not survive a user logoff. We have C++/MFC
applications which do a subclassing code trick to accomplish this but I've
not found an equivalent for C# apps.
http://support.microsoft.com/kb/q164166/
5) I have the main form's TopMost property set to true, and after 2 hrs. of
messing around, I discovered the tooltips are showing behind the form. This
is the case for XP as well as Win2k.
One unrelated thing:
1) Once in a while my VS.NET search function starts reporting something like
"no files found to search in". Strangely enough, when I press CTRL+SCROLL
LOCK it starts working again. Not a big deal once you know the trick.
I apologize if I've missed this information but I looked in the groups and
didn't see any real answers to these questions. I would greatly appreciate
any input as to whether some of this behavior falls in the category of
"that's just the way it is", or I'm not doing things correctly, or bugs to
be fixed, or need to look at workarounds. I'm using VS.NET 2003 and .NET
Framework v1.1 and the target OS is Win2k. Needless to say, I've been
frustrated to this point in creating what I "thought" to be a pretty simple
app. My fear (from a schedule standpoint) is that I have to start over in
C++. Thanks in advance for any comments or insults :- ).
- Brad Jones (not CodeGuru guy!)