Managed C++/CLI

Multiple Checkbox Controls

2-Aug-07 20:58

mooncry wrote:
i got stuck in the beginning

In the beginning there was EBCDIC; don't bother trying it ...
Then there was ASCII which got extended to ANSI. I expect all compilers to
handle that correctly.
Then there was Unicode, and Visual Studio handles that well, so try Visual Studio; the Express Editions are free. If VS has a Unicode problem, show us exact code.

Good luck!

Luc Pattyn

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BuckBrown2-Aug-07 12:13

2-Aug-07 12:13

Hi, I am using Visual Studio 2005 C++/CLI. I have a dialog box that has 32 check boxes on it. The user can select one or more check boxes or click on a button to 'Select All' or click on a button to 'Clear All'. In C++/MFC I used the following to check all 32 check boxes.

void CBinDialog::OnButtonSetAll()
{
for (int count = 0; count < 32; count++)
CheckDlgButton(IDC_CHECK_BIN1 + count, BST_CHECKED);

}

Is there a way to do this in C++/CLI? Right now I have to do the following...

void CBinDialog::OnButtonSetAll()
{
checkBoxBin1->Checked::set(true);
checkBoxBin2->Checked::set(true);
checkBoxBin3->Checked::set(true);
.
.
.
checkBoxBin32->Checked::set(true);
}

Which works fine, but it isn't very pretty or elegant.

Thanks

Buck

Luc Pattyn2-Aug-07 12:58

2-Aug-07 12:58

Hi,

there are two approaches I could recommend:

THE GRAPHICAL ONE

if the layout is such that a single rectangle could cover all the CheckBoxes
without containing anything else, just add a Panel to the form covering that
rectangular area, add all the checkboxes to the new Panel.

Now you can use a loop over all Controls inside that Panel.
If other Controls fall inside the Panel, you can still loop over them all,
but now you must check for the Control being a CheckBox.

And you must set up the Panel in such a way that it does not stand out
(unless that is exactly what you want; in that case you should consider a
GroupBox).

THE COLLECTION

You could set up a collection (say an array, a List, an ArrayList, ...)
that contains references to these checkboxes. If the checkboxes got added
using Visual Designer, an array (with an initializer) may be the easiest;
if they got added by code, a List or ArrayList would be easier.

Now you can easily loop over all these checkboxes.

Smile | :)

Luc Pattyn

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BuckBrown2-Aug-07 13:04

2-Aug-07 13:04

Thanks, I'll give these a whirl.

Buck

BuckBrown3-Aug-07 5:57

3-Aug-07 5:57

Hi Luc,

The layout is 4 columns of 8 check boxes, so using a panel sounds great. Since I already have the check boxes defined can I draw the panel over the existing check boxes and 'send to back'?

Buck

Luc Pattyn3-Aug-07 6:42

3-Aug-07 6:42

Hi Buck,

BuckBrown wrote:
'send to back'?

I don't know about that, I doubt it. The way I do it is:
- make sure your form is large enough (if necessary enlarge it temporarily), then:
- move the things that need to go into another, new, container, completely out of
the way, by selecting them all (drag a rectangle around them), then click one
of the controls and drag them all the way
- now insert the new Control (panel) and give it appropriate size
- now reselect the controls moved all out of the way, and drag them back, making
sure you release the mouse button while on top of the new Container (Panel).
- check: select one of the moved items (best is the top left inside panel),
look at its properties, it now should have small numbers for Location,
since this now is relative to panel if all went well.
- alternative check: watch the code generated by Designer, the checkboxes now
need to be added to the panel, not to the form.

Warning: it does not always succeed the first time, do one of the checks !

Smile | :)

Luc Pattyn

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BuckBrown3-Aug-07 7:31

3-Aug-07 7:31

I still don't see how to access each control without specifying its name. Think about the GetNextControl(control_name) method. It's supposed to get the next control in the tab order but you still have to supply the explicit control name (at least thats the way I read the docs). I keep playing with the Control.ControlCollection to no avail. A link to any example would be appreciated.

Thanks

Buck

BuckBrown3-Aug-07 6:57

3-Aug-07 6:57

I can't quite wrap my head around this. If I have a panel that has multiple controls the documentation say I can access the controls using the panels' controls property. But I can't find any examples that show me how. How do I access each control without using the controls' name? It would seem that something like a 'for each' checkbox in the panel check the status of the checkbox, but there's something basic here I don't understand.

Buck

Luc Pattyn3-Aug-07 8:00

3-Aug-07 8:00

Hi Buck,

this is C# code that would do it, assuming myPanel contains only CheckBoxes:

foreach (CheckBox cb in myPanel.Controls) {
    cb.Checked=false;
}

this is useful when myPanel contains also other types of Controls:

foreach (Control c in myPanel.Controls) {
    CheckBox cb=c as CheckBox; // is either c cast to CheckBox, or null
    if (cb!=null) cb.Checked=false;
}

I don't speak C++ fluently, I trust you will be able to do the same in C++.

Smile | :)

Luc Pattyn

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BuckBrown3-Aug-07 9:37

3-Aug-07 9:37

Hi Luc,

The C++/CLI syntax is...

for each(CheckBox^ cb in panelBin1->Controls)
cb->Checked::set(false);

I can see now that in order for this to work you need to declare a CheckBox^ place holder called cb that the 'for each' construct uses to copy each of the CheckBox controls into allowing access to that control. It was the declaration of this place holder that I had no idea about. I need to start thinking of types as more than just int, double, etc. Amazing that I could not find an example of this after an hour of googling.

Thanks a lot,

Buck

Luc Pattyn3-Aug-07 10:04

Dialog box query [modified]

3-Aug-07 10:04

Hi Buck,

you're welcome.

The place holder pattern (if you want to call it that) is what is needed
by "for each"; it is rather similar to the input parameters in a method.

Some remarks:
1.
for each requires each element in the collection to be of the indicated type,
it does not act like a filter (that's why my second example needed the more
general Control type, followed by a more specific type check).
2.
you can use the place holder only as a read-only variable; you can't assign
a new value to it inside the for each loop.
3.
There are some surprising uses for foreach; example:
In C# you can do foreach(char c in myString); probably that works in C++ too.
4.
Sometimes you will prefer a regular for loop over for each, since that offers
an index, which may come in handy.

And one comment: if this is new to you, I suggest you get a book on managed C++,
and work your way through it. for each is one fundamental tool, if you're
unfamiliar with it, I trust there will be more you really should know.

Good luck with the CheckBoxes and everything!

Luc Pattyn

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dona jain1-Aug-07 19:46

dona jain

1-Aug-07 19:46

i have used a text box in my dialog box in WIN32 programming....now i want that the data entered by user can be copied to a text file on pressing ok. what method can i use for this??

-- modified at 5:29 Thursday 2nd August, 2007

Re: Dialog box query

Christian Graus1-Aug-07 23:42

Christian Graus

1-Aug-07 23:42

*sigh*

Again, you're still in the wrong forum. If you're writing Win32 code, you're making two horrible mistakes

1 - using Win32 code. Why would you ?
2 - asking in the C++/CLI forum, when you're using the oldest form of writing a dialog in C++ there is. This belongs in the Visual C++ forum.

GetWindowText is how you get the text out of a textbox.

Christian Graus - Microsoft MVP - C++

"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

What is special about Dispose() methods?

BuckBrown1-Aug-07 5:02

1-Aug-07 5:02

Hi, I am using Visual Studio C++/CLI. I am now playing around with the System::Drawing::Font class and I have seen Microsoft examples that use Dispose() but when I try to invoke the System::Drawing::Font::Dispose() function the compiler gives me an "error C2039: 'Dispose' : is not a member of 'System::Drawing::Font'". Does anyone know why this happens? The intellisense shows that the Dispose() method is a member of the Font class (as well as the Microsoft docs).

Thanks

Buck

iddqd5151-Aug-07 5:20

iddqd515

1-Aug-07 5:20

Dispose() is a function inherited from the IDisposable interface. Its meant to implement the "Dispose pattern" to enable some form of immediate destructors in managed code. In C# you can call Dispose() on objects that will perform some clean up functions (like closing streams and such). In C++/CLI Dispose() is mapped to the class destructor by the compiler. You can't explicitly invoke Dispose() (nor write one). Instead, if an object encapsulating a resource needs some clean up done immediately (rather than waiting for the garbage collector) call either a Close() type function (which itself should only call the destructor I believe) or use delete (or declare the variable with stack semantics and have the destructor called automatically when the variable goes out of scope).

BuckBrown1-Aug-07 8:42

1-Aug-07 8:42

Thanks.

Mark Salsbery1-Aug-07 5:46

Mark Salsbery

1-Aug-07 5:46

This bit me a bit when I recently migrated to VS 2005.

Here's an article that may help (even though the article is about porting to 2005, it contains relevant info about destructors and Dispose):

Changes in Destructor Semantics[^]

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

BuckBrown1-Aug-07 8:43

1-Aug-07 8:43

Thanks.