C / C++ / MFC

2-Sep-09 9:58

Hi,

I try to implement a combobox where it is possible to delete items in expanded state (listbox portion of combobox is dropped down). Here what I have done: I added a keyboard handler and call DeleteString(GetCurSel()). Unfortunately the height of the listbox is never updated after items are removed. I tried to call ShowDropDown(FALSE); ShowDropDown(TRUE); as a workaround, which will update the listbox size... but it comes with an animation on Windows XP (Common Controls 6).

1) Is there a way to disable animations for a specific control?
2) Alternatively, can I get access to the listbox portion of a combobox in order to manually update its size?

Thanks for help! Smile | :)

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Code-o-mat2-Sep-09 11:46

Code-o-mat

2-Sep-09 11:46

Apparently CComboBox::GetComboBoxInfo[^] can give you a handle to the list control. Aside i would try to use GetItemHeight/SetItemHeight to see if it triggers any size recalculation in the control or not, maybe you get lucky. Another thing you could try experimenting with is CWnd::SetRedraw, you could try to disabe redrawing of the whole window, do your ShowDropDown routine and then re-enable redrawing and have the list get redrawn. I might be reinventing the wheel here but i think you can't disable animating for a single control, only for the whole system.

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Life: great graphics, but the gameplay sux. <

Moak2-Sep-09 14:11

2-Sep-09 14:11

Code-o-mat wrote:
Apparently CComboBox::GetComboBoxInfo[^] can give you a handle to the list control.

Thanks that helped! A more detailed answer in the post below. Smile | :)

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Randor 2-Sep-09 11:51

Randor

2-Sep-09 11:51

Hei Moak,

See if this works:

COMBOBOXINFO cbi = {sizeof(COMBOBOXINFO)};
if(GetComboBoxInfo(&cbi))
{
	HWND hwndListBox = cbi.hwndList;
	LRESULT lNum = SendMessage(CB_GETCOUNT,0,0);
	LRESULT lWidth = SendMessage(CB_GETDROPPEDWIDTH,0,0);
	LRESULT lHeight = SendMessage(CB_GETITEMHEIGHT,0,0);
	::SetWindowPos(cbi.hwndList,0,0,0,lWidth,lNum+1 * lHeight,SWP_NOMOVE | SWP_NOOWNERZORDER | SWP_FRAMECHANGED);
}

Moak2-Sep-09 14:02

2-Sep-09 14:02

Great this works! I changed the code slightly, CB_GETDROPPEDWIDTH returned zero.

COMBOBOXINFO cbi = { sizeof(COMBOBOXINFO) };
if(GetComboBoxInfo(GetComboBoxCtrl()->GetSafeHwnd(), &cbi))
{
	CRect rect;
	::GetWindowRect(cbi.hwndList, &rect);
	rect.bottom = rect.top + GetCount()*GetItemHeight(0) + 2;
	::SetWindowPos(cbi.hwndList, 0, 0, 0, rect.Width(), rect.Height(), SWP_NOMOVE | SWP_NOZORDER);
}

There are two thing I am not sure about and I would like to ask: In the height calculation I needed to add 2 pixels for the border, is there a better alternative than using a magic value? About the flags for SetWindowPos(), I didn't understand from MSDN what SWP_NOOWNERZORDER [^] is for? I replaced it with SWP_NOZORDER, hope this is okay.

Thanks, M

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Randor 2-Sep-09 15:00

Randor

2-Sep-09 15:00

Moak wrote:
There are two thing I am not sure about and I would like to ask: In the height calculation I needed to add 2 pixels for the border, is there a better alternative than using a magic value?

I am actually not sure about this. I do not know if the GetSystemMetrics Function[^] will return anything meaningful for the ListBox border. You can check if SM_CYFIXEDFRAME returns the correct value. Interestingly enough I did not have this problem... Hmmmm GetCount() returns a zero based index... shouldn't you be adding 1 before multiplying by height?

Moak wrote:
I didn't understand from MSDN what SWP_NOOWNERZORDER [^] is for? I replaced it with SWP_NOZORDER, hope this is okay.

Oops, yes... SWP_NOZORDER is correct... Blush | :O

Best Wishes,
-David Delaune

Moak2-Sep-09 15:17

2-Sep-09 15:17

Randor wrote:
You can check if SM_CYFIXEDFRAME returns the correct value. Interestingly enough I did not have this problem

Okay, I will check it tomorrow. Btw, GetCount()[^] returns not a zero based index.

Thanks again... time to get some sleep.

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Randor 2-Sep-09 15:23

Randor

2-Sep-09 15:23

Moak wrote:
Btw, GetCount()[^] returns not a zero based index.

Ahhh yes you are correct again. Blush | :O

Its the CB_GETCOUNT Message[^] that returns the zero based index. Smile | :)

Best Wishes,
-David Delaune

How to dispatch WM_LBUTTONDOWN message after calling ReleaseCapture()?

Code-o-mat2-Sep-09 20:34

Code-o-mat

2-Sep-09 20:34

To know the size of the border you could try this trick:

CRect Outer, Inner;

list.GetWindowRect(&Outer);
list.GetClientRect(&Inner);
list.ClientToScreen(&Inner);

int LeftBorder   = Inner.left   - Outer.left;
int TopBorder    = Inner.top    - Outer.top;
int RightBorder  = Outer.right  - Inner.right;
int BottomBorder = Outer.bottom - Inner.bottom;

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Life: great graphics, but the gameplay sux. <

includeh102-Sep-09 8:48

includeh10

2-Sep-09 8:48

A window called GetCapture() first, then calls ReleaseCapture() when mouse-down (on WM_LBUTTONDOWN message).

If mouse-down is not clicking on the window, how do we dispatch WM_LBUTTONDOWN message to that window clicked?

The question is similar to Window's menu - WM_LBUTTONDOWN is correctly dispatched if clicking outside of menu, acturally the window I asked is similar to menu for displying some information.

Re: How to dispatch WM_LBUTTONDOWN message after calling ReleaseCapture()?

Stuart Dootson2-Sep-09 9:07

Stuart Dootson

2-Sep-09 9:07

Convert the position given in the WM_LBUTTONDOWN message to screen co-ordinates. Use GetWindowFromPoint to get the window at that position. Post the WM_LBUTTONDOWN message to that window, remembering to convert the screen co-ordinates to client co-ordinates for that window.

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

Re: How to dispatch WM_LBUTTONDOWN message after calling ReleaseCapture()?

includeh103-Sep-09 7:45

includeh10

3-Sep-09 7:45

Thanks, all are fine now.

the function is WindowFromPoint(...) - first time I use it.

char char[] variables help

egerving2-Sep-09 8:26

egerving

2-Sep-09 8:26

I am a major newbie to window API and coding in C C++. I'm having a major problem with character variables. In other languages you can just say
variable char x = "Hello"
variable char y = "I'm stupid"
x="No, I'm really not stupid"
x=y

but in c a char is basically a number from the ASCII table
and if you define char x[112] you then can't say x="Hello" because I guess x must be 112 chacters. But you can say x[]="Hello" which is ok if you just want a variable for "Hello" but if you want use a variable and assign it to different values and/or concatenat different values to it what do you do.

Anyone have any simple answers as to how to use character variables in c c++?

What I want to do is create a text file that's 112 characters on each line.

1-2= a two digit code
3-12=yyyy/mm//dd
13-20=hh:mm:ss
21-40=a barcode retrieved from an editbox
41-60=blank
61-80=blank
81-81=a single digit code
82-92=a decimal 10,2 retrieved from an editbox
92-102=a number retrieved from an edit box
103-112=a number

if numbers / values are less than allowed their padded with spaces

something like this is easy in other languages but in windows api c c++ seems to be very difficult

thanks for any help

Iain Clarke, Warrior Programmer

Iain Clarke, Warrior Programmer2-Sep-09 8:47

2-Sep-09 8:47

There's not going to be all that simple an answer for you. What you are asking for is the stuff you learn in a lesson, or from a book - not from a quick post.

But here's a start.

char means character. In those other languages, "Hello" is a string, not a char either.

Another work for character is letter. So, 'H' is a char, "Hello" is a string, or bunch of characters one after another.

char message [] = "Hello";

That means that the message variable is an arrach of characters - or an array of letters. In this case, 'H' followed by 'e', 'l', 'l', 'o', and lastly a char value of 0, to denote the end of a string.

And that's all I'll reply - otherwise I'll write a book for you - and other people have already done that.
But hopefully ot will get you started on your journey.

I learned from Kernigan & Richie - small language, small book.

Now, if you want to *pay* me to write you a book...

Iain.

I have now moved to Sweden for love (awwww).
If you're in Scandinavia and want an MVP on the payroll (or happy with a remote worker), or need cotract work done, give me a job! http://cv.imcsoft.co.uk/[^]

Stuart Dootson2-Sep-09 9:01

Stuart Dootson

2-Sep-09 9:01

egerving wrote:
if you define char x[112] you then can't say x="Hello" because I guess x must be 112 chacters

No - it's because a C string, when referred to by name, is a pointer, not an array. You can use strcpy and strcat (and many other functions) to build strings.

For your situation, I'd probably use fprintf to write each record to the file, using width specifications - something like:

fprintf(fileHandle, "%-2d%-4d/%-2d/%-2d%-2d%-2d:%-2d%-20s                                        %-1d%-11.2f%-11d%%-10d\n", firstCode, year, month, day, hour, minute, second, barcode, secondCode, decimal, firstNumber, secondNumber);

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

Randor 2-Sep-09 9:09

Randor

2-Sep-09 9:09

Hi egerving,

This basic tutorial might help:

C++ Language Tutorial[^]

If you are serious about learning the C++ language here is a list of some of the best. You may want to consider purchasing some of them.

The Most Important C++ Books...Ever[^]

Best Wishes,
-David Delaune

David Crow2-Sep-09 9:50

David Crow

2-Sep-09 9:50

egerving wrote:
...and if you define char x[112] you then can't say x="Hello" because I guess x must be 112 chacters.

Valid:

char x[112] = "Hello";

Invalid:

char x[112];
x = "Hello";

egerving wrote:
...if you want use a variable and assign it to different values and/or concatenat different values to it what do you do.

For C, use functions like strcpy() and strcat(). For C++, use the string class.

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egerving2-Sep-09 11:31

egerving

2-Sep-09 11:31

Thank you all very much for your posts. Every little bit helps. I think I'm really starting to like this site as this is the second time I've made a post and got responses both times!

Thank you.