A problem with UserControls and MessageBoxes

[Tim Osborne]

Hi

I am currently investigating a very annoying problem with one of our
applications.

We have a UserControl that runs in IE.

As the control fires up the constructor does some status checking and if the
database is in
one of several states we want to notify the user.

Unfortunately there are a couple of issues with this.

Seems like when we used the native MessageBox.Show the control stops
receiving windows messages and never fully initializes. So we came up with a
class that wraps the Windows native MessageBox function in user32.dll.

This version allows the usercontrol to complete and generally behaves
correctly, everywhere but in the constructor.

If we present a message box during the constructor it does not appear to be
modal with respect to the UserControl,
so the user can continue to interact with the U.C. even though we don't want
them to.

This causes all sorts of problems.

I've got to think that maybe the U.C. handle isn't valid, and that's why the
parentage isn't being respected.

Do any of you have an possible solutions for me to try.

In old style SDK programming I'd probably just post a message back to the
U.C. and display the warning a little later,
but I don't want to have to declare a WndProc unless I absolutely have to.

Thanks

[Pulpet]

On Wed, 15 Mar 2006 08:10:32 -0500, "Tim Osborne"
<Ti*********@xcellenet.com> wrote:

And multithreading?

[scott blood]

A modal dialog box requires some form of handle to be passed to it.

Internally if you dont pass a handle the handle is usually exgtracted from
the current owner screen where the code is executed.

During the Constructor even i am pretty sure there is no handle available,
thus the modal dialog box dosn't know which screen to stay in front of, thus
its not modal in your application.

Regards

"Tim Osborne" <Ti*********@xcellenet.com> wrote in message
news:%2****************@tk2msftngp13.phx.gbl...

Hi

I am currently investigating a very annoying problem with one of our
applications.

We have a UserControl that runs in IE.

As the control fires up the constructor does some status checking and if
the database is in
one of several states we want to notify the user.

Unfortunately there are a couple of issues with this.

Seems like when we used the native MessageBox.Show the control stops
receiving windows messages and never fully initializes. So we came up with
a class that wraps the Windows native MessageBox function in user32.dll.

This version allows the usercontrol to complete and generally behaves
correctly, everywhere but in the constructor.

If we present a message box during the constructor it does not appear to
be modal with respect to the UserControl,
so the user can continue to interact with the U.C. even though we don't
want them to.

This causes all sorts of problems.

I've got to think that maybe the U.C. handle isn't valid, and that's why
the parentage isn't being respected.

Do any of you have an possible solutions for me to try.

In old style SDK programming I'd probably just post a message back to the
U.C. and display the warning a little later,
but I don't want to have to declare a WndProc unless I absolutely have to.

Thanks

[Tim Osborne]

Oh I quite understand there is no valid handle, and that's why its not
modal.

I was wondering if anyone had a solution, other than my 'PostMessage'
approach.

Which BTW I've just finished coding, and it seems to work.

It just seems like a bit of a kludge and my project lead might not like it
when I explain it to him, so I'm looking for
alternatives.

Thanks
"scott blood" <sc*********@hotmail.com> wrote in message
news:eJ*************@TK2MSFTNGP12.phx.gbl...

A modal dialog box requires some form of handle to be passed to it.

Internally if you dont pass a handle the handle is usually exgtracted from
the current owner screen where the code is executed.

During the Constructor even i am pretty sure there is no handle available,
thus the modal dialog box dosn't know which screen to stay in front of,
thus its not modal in your application.

Regards

"Tim Osborne" <Ti*********@xcellenet.com> wrote in message
news:%2****************@tk2msftngp13.phx.gbl...

Hi

I am currently investigating a very annoying problem with one of our
applications.

We have a UserControl that runs in IE.

As the control fires up the constructor does some status checking and if
the database is in
one of several states we want to notify the user.

Unfortunately there are a couple of issues with this.

Seems like when we used the native MessageBox.Show the control stops
receiving windows messages and never fully initializes. So we came up
with a class that wraps the Windows native MessageBox function in
user32.dll.

This version allows the usercontrol to complete and generally behaves
correctly, everywhere but in the constructor.

If we present a message box during the constructor it does not appear to
be modal with respect to the UserControl,
so the user can continue to interact with the U.C. even though we don't
want them to.

This causes all sorts of problems.

I've got to think that maybe the U.C. handle isn't valid, and that's why
the parentage isn't being respected.

Do any of you have an possible solutions for me to try.

In old style SDK programming I'd probably just post a message back to the
U.C. and display the warning a little later,
but I don't want to have to declare a WndProc unless I absolutely have
to.

Thanks