Re: Serialization of enumerated types - C / C++ / MFC Discussion Boards

Re: Serialization of enumerated types

C^hris L^osinger26-Sep-07 8:14

C^hris L^osinger

26-Sep-07 8:14

bob16972 wrote:
Are you on 6.0 or 2003

doesn't matter. this is a pretty basic C++ issue, the kind of thing you run into everywhere.

// reading
int t;
ar >> t;
enumVal = (enumType)t;

// storing
ar << (int)enumVal;

image processing toolkits | batch image processing

Re: Serialization of enumerated types

bob1697226-Sep-07 8:36

bob16972

26-Sep-07 8:36

My apologies.
I would never have suspected that was necessary but I live and learn.

Thank you very much for helping me over that hurdle.

Re: Serialization of enumerated types

David Crow26-Sep-07 6:02

David Crow

26-Sep-07 6:02

Do you have something similar to:

class CSomething
{
public:
 
    enum
    {
        ONE,
        TWO,
        THREE
    } SomeType;
 
    void Serialize( CArchive &ar )
    {
        if (ar.IsStoring())
            ar << (int) SomeType;
        else
            ar >> (int) SomeType;
    }
};

"A good athlete is the result of a good and worthy opponent." - David Crow

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

Re: Serialization of enumerated types

bob1697226-Sep-07 8:05

bob16972

26-Sep-07 8:05

That's basically it. I needed a typedef in front of the enum. I've tried a couple variations which should effectively be the same thing in the end but none get me past the error.

I tried the cast operation an it didn't change the error.

I'm not sure if this matters, but I've noticed from past posts you use VC++ 6.0 exclusively and this project is on Visual C++ 2003, so if that's working for you in your environment, I'll give it try in a Visual C++ 6.0 project to see if the 2003 compiler just changed the rules.

Re: Serialization of enumerated types

David Crow26-Sep-07 8:28

David Crow

26-Sep-07 8:28

bob16972 wrote:
...if that's working for you in your environment, I'll give it try in a Visual C++ 6.0 project...

You might have to tweak it a bit like:

if (ar.IsStoring())
{
    int x = SomeType;
    ar << x;
}
else
{
    int x;
    ar >> x;
    SomeType = (_SomeType) x;
}

"A good athlete is the result of a good and worthy opponent." - David Crow

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

Re: Serialization of enumerated types

bob1697226-Sep-07 8:37

bob16972

26-Sep-07 8:37

I feel silly now but a tad bit smarter.

Thanks for helping me out. I learned something new.

Re: Serialization of enumerated types

Nelek26-Sep-07 20:16

Nelek

26-Sep-07 20:16

Why have you written the underscore in the casting by loading???

I mean: SomeType = (_SomeType) x;

Greetings.

--------
M.D.V.

If something has a solution... Why do we have to worry about?. If it has no solution... For what reason do we have to worry about?

Help me to understand what I'm saying, and I'll explain it better to you

Wink | ;)

Re: Serialization of enumerated types

David Crow27-Sep-07 2:27

David Crow

27-Sep-07 2:27

Nelek wrote:
Why have you written the underscore in the casting by loading???

To differentiate between a type and a value.

"A good athlete is the result of a good and worthy opponent." - David Crow

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

Re: Serialization of enumerated types

Nelek27-Sep-07 3:10

Nelek

27-Sep-07 3:10

Thanks

LVN_ONITEMCHANGING

paper6726-Sep-07 4:54

paper67

26-Sep-07 4:54

Hi,

Is there a possibility to get the previous item selection in a LVN_ONITEMCHANGING handler.
The handler provides the item that is about to change from unselected to selected, but I can not
find a way to get the item that loses the selection.

void CMPRSDlg::OnItemChangingMPRSLst(NMHDR *pNMHDR, LRESULT *pResult)
{
NM_LISTVIEW *pNMListView = (NM_LISTVIEW *) pNMHDR;

*pResult = 0;

// TODO : Add your control notification handler code here.
if (pNMListView->uChanged & LVIF_STATE)
{
int nItem = pNMListView->iItem;

// An item's state is about to change.
if (!(pNMListView->uOldState & LVIS_SELECTED) && (pNMListView->uNewState & LVIS_SELECTED))
{
// Item will go from unselected to selected.
ASSERT(::IsWindow(m_ctlMPRSLst.m_hWnd));

POSITION pos = m_ctlMPRSLst.GetFirstSelectedItemPosition();
/// THIS DOES NOT WORK. pos = NULL ???? Is there another way ?
:
:

// Prevent selection if the item is locked.
CMPRSEntry *pEntry = (CMPRSEntry *) m_ctlMPRSLst.GetItemData(nItem);

if (pEntry->m_SKU.IsLocked())
{
*pResult = 1;
return;
}
}
}
}

Re: LVN_ONITEMCHANGING

Nelek26-Sep-07 5:37

Nelek

26-Sep-07 5:37

If the number of items is not very big and the time is not critical you can deal with it using a help-array.

I mean:

void CMPRSDlg::OnItemChangingMPRSLst(NMHDR *pNMHDR, LRESULT *pResult) 
{
//just at the beginning of the function
for (int i = 0; i < number_of_items; i++)
{
if (Help_array[i] == 1)
{
last_item = i;
Help_array[i] = 0;
break;           //When you find an old selected item break to have the index
}
last_item = -1;  //There was no selection before;
}
//your code to get the item that is changing

Help_array[index_of_changing_item] = 1; //Last line of your function, this will be the last selected item in the next OnChangingItem...
}

Where Help_Array has zero in ALL positions at the beggining.

Hope it helps.

Re: LVN_ONITEMCHANGING

Mark Salsbery26-Sep-07 5:46

Mark Salsbery

26-Sep-07 5:46

You can always store the HITEM of the currently selected item, which will be
the last selected item when a new item is selected.

Mark

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

Re: LVN_ONITEMCHANGING

paper6726-Sep-07 6:36

paper67

26-Sep-07 6:36

yes, but where to I have to do this.
I want to achieve the following :
I want to prevent that in a multiselection CListCtrl some items which have a particular
flag set bound to the item with SetItemData() are getting selected. But selection can occur in many different ways. Through a mouseclick, through the keyboard interface and particular with the Ctrl and Shift keys. I can not find a place to do the saving which handles all these cases.

tia

Re: LVN_ONITEMCHANGING

Mark Salsbery26-Sep-07 7:12

Mark Salsbery

26-Sep-07 7:12

I'm not understanding what you want to do.

Do you want to prevent items from being selected?

You get a notification when the state of an item is about to change, which you can prevent.
You also get a notification when an item's state is changed.

You can use LVM_GETSELECTEDCOUNT and LVM_GETNEXTITEM to enumerate the selected items.

Can you implement the logic you want using these?

Mark

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

Re: LVN_ONITEMCHANGING

paper6726-Sep-07 7:44

paper67

26-Sep-07 7:44

Yes, I want to prevent multiple items from being selected by skipping the unwanted ones and
setting the selection back to the first item which is wanted( without flag), depending on the direction of the selection.

Re: LVN_ONITEMCHANGING

Mark Salsbery26-Sep-07 8:05

Mark Salsbery

26-Sep-07 8:05

paper67 wrote:
I want to prevent multiple items from being selected

Always or sometimes?

If always, then the LVS_SINGLESEL style should be used for the control.

If sometimes, the control isn't going to keep track of this for you AFAIK.

Depending on the complexity of the logic involved, you may need to handle
item selection yourself, overriding the control's default behavior.

Default List-View Message Processing[^]

Mark

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

Re: LVN_ONITEMCHANGING

Nelek26-Sep-07 20:25

Nelek

26-Sep-07 20:25

Don't you like my first answer? or is not what you need? Is a bypass and may take a bit of time in performance, but it can work.

operator delete

Waldermort26-Sep-07 4:13

Waldermort

26-Sep-07 4:13

Just to confirm if this is standard behaviour.

I have a large linked list of some 100,000 objects, each allocated with new. When deleting this list, in debug mode it takes a good 15 seconds causing the app to appear hung. yet in release mode it takes a fraction of second.

I know that with DEBUG set, a lot of extra validation is going on behind the scenes, but should it really cause this much of a slowdown?

Waldermort

Re: operator delete

Maximilien26-Sep-07 4:25

Maximilien

26-Sep-07 4:25

yes.

never trust a DEBUG version for performance.

Maximilien Lincourt
Your Head A Splode - Strong Bad

Re: operator delete [modified]

Randor 26-Sep-07 5:26

Randor

26-Sep-07 5:26

Here is what happens when you call operator new when _DEBUG is defined. (As I understand it)

1.) _malloc_dbg() is invoked and your size_t is passed through.
2.) An object is created of struct type _CrtMemBlockHeader.
3.) The memory you have requested is allocated and memset() to 0xCD. (C = Clean)
4.) 4 bytes on both sides of the memory you requested are memset() to 0xFD (F = Fence)
5.) A pointer to the _CrtMemBlockHeader is added to an internal linked list for tracking.
6.) A pointer to the memory you requested is returned.

When the memory is released here is what happens:

1.) _free_dbg is invoked and passed the address.
2.) The debug heap manager walks through the linked list and finds the pointer to the CrtMemBlockHeader struct.
3.) Checks are made on both sizes of the memory you requested to make sure the Fence 0xFD is still there.
4.) The memory location is memset() to 0xDD (D = Dead)
5.) The _CrtMemBlockHeader is marked as freed in the heap managers linked list. But the struct remains in memory.

Upon application termination the entire linked list is walked and inspected for memory which was not freed or missing its fence.

Hope this helps you,
-Randor (David Delaune)

Re: operator delete

Waldermort26-Sep-07 6:23

Waldermort

26-Sep-07 6:23

That's a good description Smile | :)

Now I can see why it takes so long, walking a linked list of 100,000 items must add quite an overhead.

Another reason why delete was taking so long was due to using vld.

Perhaps a mapped file may better suit my needs...

Waldermort

syatem level Hooks related issue

Sharad Goyal26-Sep-07 4:00

Sharad Goyal

26-Sep-07 4:00

Hi,
I am trying to get any message or a point where I can found system generated window poping up (i.e. net send window) I tried system hooks ( CBT ,SHELL) these are not working for these situation. can some one help me??

Sharad goyal

Re: syatem level Hooks related issue

ThatsAlok26-Sep-07 19:35

ThatsAlok

26-Sep-07 19:35

Sharad Goyal wrote:
net send window

actually you can hook creation messagebox that could help you!

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cheers,
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VC Forum Q&A :- I/IV
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the function FILE

youbo26-Sep-07 3:01

youbo

26-Sep-07 3:01

like this:FILE*in ,what does it mean? and the function is include in which file?

Re: the function FILE

jhwurmbach26-Sep-07 3:34

jhwurmbach

26-Sep-07 3:34

in is a variable of type "pointer to FILE"
FILE is defined in stdio.h

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