C / C++ / MFC

Assertion error on controls

27-Aug-02 8:08

kuphryn wrote:
Hmmmm. I thought reference has always been optimized and is faster than a pointer

Faster to type, maybe. Smile | :)

Tomasz Sowinski -- http://www.shooltz.com

Free your mind and your ass will follow.

RalfPeter27-Aug-02 7:03

RalfPeter

27-Aug-02 7:03

Does anyone know the possible reason why I'm getting assertion error messages when trying to access control variables from a dialog? E.g., I have a CCombo box (myCombo) in a dialog class. When I issue the command 'myDialog.myCombo.GetCurSel()' after a myDialog.DoModal() command, I get an assertion failure message. Do I have to somewhere instantiate the control variables? Thx,
Ralf.

ralf.riedel@usm.edu

Re: Assertion error on controls

Tomasz Sowinski27-Aug-02 7:07

CTreeCtrl and item images

27-Aug-02 7:07

After DoModal returns, your controls are no longer windows (in Win32 API sense - they aren't associated with HWNDs).

Map your combo to int variable in ClassWizard or call GetCurSel in DoDataExchange/OnOK.

Tomasz Sowinski -- http://www.shooltz.com

Free your mind and your ass will follow.

Mariusz Popiołek27-Aug-02 6:56

Mariusz Popiołek

27-Aug-02 6:56

I don't want to have treectrl where all items have its own images, I just want to add images to selected items, but I don't know if this is possible. Thanks for any help.

Tomasz Sowinski27-Aug-02 7:09

27-Aug-02 7:09

You may try with passing invalid image index (like -1) to SetItemImage or InsertItem. Your image-less item will be indented, however.

Tomasz Sowinski -- http://www.shooltz.com

Free your mind and your ass will follow.

Mariusz Popiołek27-Aug-02 7:41

Mariusz Popiołek

27-Aug-02 7:41

That's what I'm trying to avoid, I don't want to have indented item (I coined similar solution with invalid index but of course I got indented item), I'm affraid that this is impossible, but anyway thanks

Shog⁹27-Aug-02 7:55

Shog⁹

27-Aug-02 7:55

Well, there's always custom draw. Might be a lot of work for minimal gain though.

Shog⁹

Let me hear you / Make decisions / Without your television

Join Team CodeProject

pnpfriend27-Aug-02 9:29

pnpfriend

27-Aug-02 9:29

It is possible .. but you have to have images though..Draw any images that you want..
then onInitDialog() add this line..

m_ImageList.Create(IDB_BITMAP_LIST,16,2,RGB(255,255,255));<br />
<br />
// anywhere( in any function you want ) put these lines<br />
HTREEITEM hItem; <br />
// set hItem equal to any treeitem that you want to change the image...<br />
m_TreeCtrl.SetItemImage(hItem,IMAGEFILE,IMAGEFILE);  // IMAGEFILE.. could be 1, 2, 3, 4,.or up to the number of your image list has.<br />

hope it helps

Tomasz Sowinski27-Aug-02 9:34

Puzzled me! (about CTreeCtrl)

27-Aug-02 9:34

Did you actually read the question?

Tomasz Sowinski -- http://www.shooltz.com

Free your mind and your ass will follow.

Pole27-Aug-02 6:38

Pole

27-Aug-02 6:38

I add the TVS_CHECKBOXES style,the checkboxes of the TreeCtrl looks nice.But when I create a CImageList and associated it with TreeCtrl,the checkboxes looks ugly(the mark looks small).
How to solve this problem? Cry | :((

Sincerely,Pole.

STL gurus map operator []

_Magnus_27-Aug-02 5:43

27-Aug-02 5:43

In a map with int both as key and data, what is the result of
int i = map[index]
when index is not in the map?
In the VC 6 STL impl. i equals to 0, is that what it should be or
is the result undefined?

If it is undefined, what use is the [] operator really?

/Magnus

- I don't necessarily agree with everything I say

Tomasz Sowinski27-Aug-02 5:56

27-Aug-02 5:56

From the VC6 STL docs:

The member function determines the iterator it as the return value of insert( value_type(key, T())).

So, if element with given key is not present, it'll be constructed using default c'tor. In the case of simple types like int, it means zeroing the bits.

Tomasz Sowinski -- http://www.shooltz.com

Free your mind and your ass will follow.

_Magnus_27-Aug-02 6:02

27-Aug-02 6:02

Ok, good, then i can write some cleaner code.
Things like this return value of insert( value_type(key, T())). make my head hurt. Smile | :)

/Magnus

- I don't necessarily agree with everything I say

Tomasz Sowinski27-Aug-02 6:03

27-Aug-02 6:03

_Magnus_ wrote:
Things like this return value of insert( value_type(key, T())). make my head hurt

This behavior is by design Wink | ;)

Tomasz Sowinski -- http://www.shooltz.com

Free your mind and your ass will follow.

C^hris L^osinger27-Aug-02 5:57

C^hris L^osinger

27-Aug-02 5:57

_Magnus_ wrote:
If it is undefined, what use is the [] operator really?

i have no idea. i always use the long form:

myMapIterator it = myMap.find(value);
if (it == myMap.end())
{
not in the map
}

no question about the meaning of the return code.

-c

Aiei i ea eio aoa i e eio e aigoa

image effects!

_Magnus_27-Aug-02 6:04

27-Aug-02 6:04

I have always done it like that to since i was unsure of the [] operator, but i rather use the [] operator since the code will look cleaner.

/Magnus

- I don't necessarily agree with everything I say

sie27-Aug-02 6:19

sie

27-Aug-02 6:19

Don't forget that the index has now been added to the map i.e. the map size has increased by one. In the case you outline this may not be significant but it can be significant in other cases as the map may grow in an uncontrolled manner.

_Magnus_27-Aug-02 6:21

27-Aug-02 6:21

Yes, i am aware of that, but as you said it does not really matter in this case.

/Magnus

- I don't necessarily agree with everything I say

Jim Crafton27-Aug-02 6:20

Jim Crafton

27-Aug-02 6:20

It may "look" cleaner, but I would agree with Chris, using the long is MUCH clearer as too what is actually going on.
For example if you have
map<int,fooobject*> fooMap

what will
FooObject* foundFoo = fooMap[3];

actually be ?
I would expect that foundFoo would be NULL if there is no entry for the value 3, but is that what will actually happen ?
If you use the long form, it is a couple more lines of code, but you KNOW exactly what will happen - no guessing.

_Magnus_27-Aug-02 6:25

27-Aug-02 6:25

In this case i have a map with rightbits and i think that

if(map[i] & bit)

is cleaner than

iterator it = map.find(i)
if(it != map.end())
{
   if((*it).second & bit)
}

But it might depend on what is in the map.

/Magnus

- I don't necessarily agree with everything I say

Tomasz Sowinski27-Aug-02 6:26

27-Aug-02 6:26

But operator[] adds an element to the map if it's not there - it's not the exact equivalent of longer version.

Tomasz Sowinski -- http://www.shooltz.com

Free your mind and your ass will follow.

Tomasz Sowinski27-Aug-02 6:25

27-Aug-02 6:25

Jim Crafton wrote:
would expect that foundFoo would be NULL if there is no entry for the value 3, but is that what will actually happen ?

Yes, it will happen. Check with the following function template:

template <class T>
void test(T t = T())
{
	T t2 = t;
}

...

test<char *>();
test<int>();
test<int>(5);

And put the breakpoint inside test. T() where T is simple type like pointer or int results in value initialized to zero.

Tomasz Sowinski -- http://www.shooltz.com

Free your mind and your ass will follow.

Jim Crafton27-Aug-02 6:28

Jim Crafton

27-Aug-02 6:28

Cool, excellent ! This is a standard for how implementers must implement a map? So we can count on this behaviour?

Tomasz Sowinski27-Aug-02 6:30

27-Aug-02 6:30

You can count on proper behavior of T() when T is simple type. This applies to this map situation.

To have even more fun, check the following declarations - they'll work:

int i = int();
typedef char *pchar;
pchar pc = pchar();

Tomasz Sowinski -- http://www.shooltz.com

Free your mind and your ass will follow.