Closing all forms

  • Thread starter Thread starter kronecker
  • Start date Start date
K

kronecker

I found this nifty routine that closes a form one by one every time it
is called. However, I need to hide them instead of closing them. Is
there a way to alter the code? I assume it has something to do with
this line here...


PostMessage(i, CInt(&H10), vbNullString, vbNullString)

Thanks

k


Public Sub closeallforms()
Dim objType As Type() =
Reflection.Assembly.GetExecutingAssembly.GetTypes()
Dim x As Integer, i As Integer
Try
For x = LBound(objType) To UBound(objType)
If Not objType(x).Name = Me.Name Then '/// make sure
you dont unload this form yet.
i = FindWindow(vbNullString, objType(x).Name)
PostMessage(i, CInt(&H10), vbNullString,
vbNullString)
End If
Next
Catch ex As Exception
MessageBox.Show("Oops, the following error occured:" &
ex.Message)
Finally
'MyBase.Close() '/// now that all the other forms are
closed , unload this one.
End Try
End Sub
 
I found this nifty routine that closes a form one by one every time
it is called. However, I need to hide them instead of closing them.
Is there a way to alter the code? I assume it has something to do
with this line here...


PostMessage(i, CInt(&H10), vbNullString, vbNullString)
Click to expand...

I do not even quote this really _awesome_ code.

Sorry for not answering your other question, yet. I thought that you
should really get into some OOP basics and learn about variable scope
before writing more lines of code.

Well, where do I start...? Sorry, if you already know some of the
following things:

First, which VB version do you have? in VB 2008 (or maybe 2005) there is
the OpenForms property (please use symbol search to find it). However,
I've never used it because I've never needed a property like that.
However, of course, you can use the OpenForms property.

Second, a UI thread (user interface) has a message loop. The OS is
message based. The message loop (see F1) is a loop that processes all
messages put into a queue by the OS. In the Framework, the message loop
is inside Application.Run (see object browser). There are overloaded
versions: One has no args, one has one arg expecting a Form object. The
one w/o args runs til the thread calls Application.ExitThread. The other
one does it's job til the passed Form has been closed.

3rd, "application framework". If enabled, you can choose the startup
Form. There is an additional option that says "til all Forms have been
closed" (or similar). VB will create an invisible Sub Main - the UI
thread's main procedure that every thread has - that behaves like
instructed in the project's properties. If the "application framework"
is disabled, you can set your own Sub Main where you can, for example,
open a database connnection before showing any form or whatever.

Now, which version did you choose? Why do you need to "close all
Forms", as the subject says? Or, maybe you have an additional NotifyIcon
in the task bar? If you have a startup Form (therefore the explanation
above), just close that one. If you have your own Sub Main, show us how
it looks like.

To be able to answer your other question, please describe the scenario
as detailled as possible. I mean, which Form opens from where and which
one needs to close another one? Do you have an MDI From? Currently, I
can only give the multi-purpose answer: If you need a reference to an
object, you have to make it available. How to do it, depends on the
situation.

(sry for a lot to read; I always like writing about one of my favorite
topics. ;-) )


Armin
 
I do not even quote this really _awesome_ code.

Sorry for not answering your other question, yet. I thought that you
should really get into some OOP basics and learn about variable scope
before writing more lines of code.

Well, where do I start...? Sorry, if you already know some of the
following things:

First, which VB version do you have? in VB 2008 (or maybe 2005) there is
the OpenForms property (please use symbol search to find it). However,
I've never used it because I've never needed a property like that.
However, of course, you can use the OpenForms property.

Second, a UI thread (user interface) has a message loop. The OS is
message based. The message loop (see F1) is a loop that processes all
messages put into a queue by the OS. In the Framework, the message loop
is inside Application.Run (see object browser). There are overloaded
versions: One has no args, one has one arg expecting a Form object. The
one w/o args runs til the thread calls Application.ExitThread. The other
one does it's job til the passed Form has been closed.

3rd, "application framework". If enabled, you can choose the startup
Form. There is an additional option that says "til all Forms have been
closed" (or similar). VB will create an invisible Sub Main - the UI
thread's main procedure that every thread has - that behaves like
instructed in the project's properties. If the "application framework"
is disabled, you can set your own Sub Main where you can, for example,
open a database connnection before showing any form or whatever.

Now, which version did you choose? Why do you need to "close all
Forms", as the subject says? Or, maybe you have an additional NotifyIcon
in the task bar? If you have a startup Form (therefore the explanation
above), just close that one. If you have your own Sub Main, show us how
it looks like.

To be able to answer your other question, please describe the scenario
as detailled as possible. I mean, which Form opens from where and which
one needs to close another one? Do you have an MDI From? Currently, I
can only give the multi-purpose answer: If you need a reference to an
object, you have to make it available. How to do it, depends on the
situation.

(sry for a lot to read; I always like writing about one of my favorite
topics. ;-) )

Armin
Click to expand...

I have an application which uses Windows media player on a separate
form + other bits and pieces also on separate forms. I can close them
all using the above code but for some reason when I close windows
media player it will not open again unless I re-start the program.
Therefore hiding it is a better thing to do so hiding rather than
closing will do for me.
However, one of my forms will not hide using the usual formx.hide( )
method (it won't close either). So how to hide all the forms one by
one...


K.
 
I have an application which uses Windows media player on a separate
form + other bits and pieces also on separate forms. I can close
them all using the above code but for some reason when I close
windows media player it will not open again unless I re-start the
program. Therefore hiding it is a better thing to do so hiding
rather than closing will do for me.
However, one of my forms will not hide using the usual formx.hide( )
method (it won't close either). So how to hide all the forms one by
one...
Click to expand...

What's the project's startup object? From where do you open the WMP Form
and the others? From where do you want to close them? Do you have an MDI
Form? I do understand that you want to hide a Form (or some), but the
relations between the Forms is still not clear to me. Which of the Forms
"lives" always? Do you specify a Form as the Owner of other(s)? Are
there modal Forms (related to the problem)?


Armin
 
What's the project's startup object? From where do you open the WMP Form
and the others? From where do you want to close them? Do you have an MDI
Form? I do understand that you want to hide a Form (or some), but the
relations between the Forms is still not clear to me. Which of the Forms
"lives" always? Do you specify a Form as the Owner of other(s)? Are
there modal Forms (related to the problem)?

Armin
Click to expand...

Ok I figured it out. Clear all forms at once like this



Private Const SW_HIDE As Integer = 0

Private Const SW_RESTORE As Integer = 9

Private Declare Function FindWindow Lib "user32.dll" Alias
"FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As
String) As Integer

<DllImport("User32")> _
Private Shared Function ShowWindow(ByVal hwnd As Integer, ByVal
nCmdShow As Integer) As Integer

Private Const SW_HIDE As Integer = 0

Private Const SW_RESTORE As Integer = 9


Public Sub hideallforms()
' Actually this hides them one by one
Dim objType As Type() =
Reflection.Assembly.GetExecutingAssembly.GetTypes()
Dim x As Integer, i As Integer

Try
For x = LBound(objType) To UBound(objType)
If Not objType(x).Name = Me.Name Then '/// make sure
you dont unload this form yet.
i = FindWindow(vbNullString, objType(x).Name)
ShowWindow(i, SW_HIDE)

End If
Next
Catch ex As Exception
MessageBox.Show("An error occured hiding forms:" &
ex.Message)

End Try
End Sub
Works a treat and you can restore them all at once too using
SW_RESTORE. Now that wasn't hard was it..

k.
 
Works a treat and you can restore them all at once too using
SW_RESTORE. Now that wasn't hard was it..
Click to expand...

If you had answered some questions, I would have been able to give a
solution, too. Anyway, problem seems to be "solved"...


Armin
 
If you had answered some questions, I would have been able to give a
solution, too. Anyway, problem seems to be "solved"...

Armin
Click to expand...

Thanks but I was after a general method rather than just specific to a
particular case.

K.
 
Kronecker,

Be aware that in Net almost everything exists from arrays, collections and
lists (and generic versions of that)

Every form has a childcollection, therefore this should do it if you have
started your childforms from a form.

\\\
For i = Me.OwnedForms.Count To -1 Step -1
Me.OwnedForms(i).Close()
Next
///


Backwards to be sure you peeling everytime one from the collection, confirm
the so by me called "Armin Zingler" method.

(Not tested by the way)

Cor
 
Thanks but I was after a general method rather than just specific to
a particular case.
Click to expand...

I think it's a very bad method in any case. But again, use it if it
works for you.

Maybe I should be fair and give some reasons:
- There are managed ways instead of using pInvoke.
- hWnd must be IntPtr. Yes, Integer works on a 32-bit System. Not on
64-bit systems. I'd always use Intptr without thinking about the
destination platform
- Well... the whole approach is b...sh.. Yes, even if it works. Sry, I
can't explain - but I bet i'd win every voting 95:5. ;-)



Armin
 
Cor Ligthert said:
Backwards to be sure you peeling everytime one from the collection,
confirm the so by me called "Armin Zingler" method.
Click to expand...

I'm still trying to understand whether this a positive or negative
statement. ;)


Armin
 
Armin,

I will make it easier for you, I don't know if you invented it, but in my
idea was you the first one from which I readed it.

Therefore I call it an Armin Zingler method.

I have to Herfried methods, which is the UrlEncoded and there is an terrible
good solution he had with the favorites.

When I have to do something with Serializing, then I always have to think on
Tom.

So decide your self if it is a positive or negative statement.

:-)

Cor
 
I think it's a very bad method in any case. But again, use it if it
works for you.

Maybe I should be fair and give some reasons:
- There are managed ways instead of using pInvoke.
- hWnd must be IntPtr. Yes, Integer works on a 32-bit System. Not on
64-bit systems. I'd always use Intptr without thinking about the
destination platform
- Well... the whole approach is b...sh.. Yes, even if it works. Sry, I
can't explain - but I bet i'd win every voting 95:5. ;-)

Armin
Click to expand...

I kind of agree but it works for the present - yes it's a bodge and
not elegant.

K.
 
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