Creating a Hidden Modeless Form

[Joel Matthias]

Hi,

I know this topic has been covered in various forms but I still can't
seem to come up with a solution that works correctly.

I want to create a modeless hidden form in my application. This is NOT
the main application form. The best way so far is as follows.

MyForm form = new MyForm();
form.Show();
form.Visible = false;

This works but the form is visible for a brief period. Even when I make
the form size 0,0 it's still visible for a brief time.

So is it possible to create a hidden .NET form that is never displayed
to the user?

Thanks - Joel

 

[Jim Hughes]

Hi,

I know this topic has been covered in various forms but I still can't
seem to come up with a solution that works correctly.

I want to create a modeless hidden form in my application. This is NOT
the main application form. The best way so far is as follows.

MyForm form = new MyForm();
form.Show();
form.Visible = false;

This works but the form is visible for a brief period. Even when I make
the form size 0,0 it's still visible for a brief time.

So is it possible to create a hidden .NET form that is never displayed
to the user?

Thanks - Joel

Just don't call the Show() method.

 

[Joel]

Hi,

I did try this and if Show() is not called the form is not created. I
have double checked this by using Spy++ and my overriding WndProc() and
placing a breakpoint there. Show() or ShowDialog() is required to
create the window.

Thanks

Joel

 

[Jim Hughes]

Hi,

I did try this and if Show() is not called the form is not created. I
have double checked this by using Spy++ and my overriding WndProc() and
placing a breakpoint there. Show() or ShowDialog() is required to
create the window.

By any chance are you trying to make this your startup form and start a
message loop on it with Application.Run?

In that case, you are right.

I assumed that the "hidden" form was an additional form in your project. In
that scenario, the second form is loaded and all properties and methods are
available and functioning.

 

[Joel]

Hi,

It is NOT the main startup form. If you do not call Show() or
ShowDialog() the underlying window is not created and hence there is no
message loop for it. I need the message loop to function so I can
intercept a broadcast message.

Joel

 

[Bob Powell [MVP]]

You could create a form or even a NativeWindow based class and show it but
position it offscreen. This is a well known technique.

--
Bob Powell [MVP]
Visual C#, System.Drawing

Ramuseco Limited .NET consulting
http://www.ramuseco.com

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[Joel]

Hmmm, now why didn't I think of that!

Thanks

 

[Terry]

Why create a Form so you can intercept a broadcast message? Why not
just write a class that creates a thread and a socket to receive it? No
form is needed then.

 

[cryolitte]

Hi Joel,

Have you tried form.CreateHandle() without form.Show()?
After form.CreateHandle() my breakpoints in WndProc() were reached
without the form being visible.