C / C++ / MFC Discussion Boards

Re: ^!^ help-- how to synchronize session between multi server.??

Tomasz Sowinski1-Aug-01 2:43

1-Aug-01 2:43

any constructive idea/discussion is warmly welcome

With all technical details you've provided, I have only one constructive idea: use some synchronization mechanism.

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

Re: ^!^ help-- how to synchronize session between multi server.??

aff1-Aug-01 20:26

aff

1-Aug-01 20:26

hu~,
thanks for ur reply, any way. if u really want to discuss
with me, i should explain the environment in detail.
i m developing a web application service. there are
many front server, being loadbalanced.
i need to maintain a session object between multi server.
the session is generated by server and user use this
session object to request server.
any other idea??

i love this site!@

How to use ACROBAT PDF ActiveX component in a Dialog.exe application?

31-Jul-01 18:50

Can somebody help how to add Acrobat reader ActiveX control to my dialog.
I installed 5.0. When to to add this control from "Registered ActiveX Controls", an error pops up "Unable to open this ActiveX control. Make sure the control contains a valid type library".

Appreciate any suggestions.

xiang

Re: How to use ACROBAT PDF ActiveX component in a Dialog.exe application?

Christian Graus2-Aug-01 18:19

Christian Graus

2-Aug-01 18:19

The control does not contain enough information for you to reuse it. I'd suggest this is by design.

Christian

#include "std_disclaimer.h"

The careful application of terror is also a form of communication.

Eagles may soar, but weasels don't get sucked into jet engines.

WTL - dynamically creating buttons etc.

Christian Graus31-Jul-01 18:03

Christian Graus

31-Jul-01 18:03

I've been looking through the examples her at Code Project, but I can't see one that shows me how to create a button or a test edit window entirely in code (i.e. not on the dialog template).

Can someone help me out here ?

Christian

#include "std_disclaimer.h"

The careful application of terror is also a form of communication.

Eagles may soar, but weasels don't get sucked into jet engines.

Re: WTL - dynamically creating buttons etc.

Christian Graus31-Jul-01 18:22

Christian Graus

31-Jul-01 18:22

OK - got that working like this:

RECT rc = {10, 10, 50, 50};
m_btn.Create(m_hWnd, rc, "", WS_CHILD | WS_VISIBLE);
m_btn.ShowWindow(SW_SHOW);

I actually didn't notice that I was creating a button on screen in the corner - why isn't WS_CHILD a default value ?

Anyhow, now I need to know how to get messages from the button in my dialog. From memory it's subclass window, is that right ?

I'm editing this message now - it's not SubclassWindow, which allows me to attach a variable to a control on the dialog. I want to create a CButton and capture it's being pressed ( actually I want to be able to do that to lots of them ). Can anyone suggest how this is done ?\

Editing yet again. I discovered if I overrode WM_COMMAND I could catch the button press, with lParam equalling the hWnd of the button. I've used this prototype:

LRESULT OnCommand(UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL& /*bHandled*/)

and found that wParam is always 0 and uMsg is 0x0111 ( WM_COMMAND ). Surely WM_COMMAND will be called for things other than buttons ? How can I tell how I got there so I can respond intelligently to the event ?

Thanks

Christian

#include "std_disclaimer.h"

The careful application of terror is also a form of communication.

Eagles may soar, but weasels don't get sucked into jet engines.

Re: WTL - dynamically creating buttons etc.

Tommy H D Svensson2-Aug-01 9:35

Tommy H D Svensson

2-Aug-01 9:35

I tried to do like you did:

RECT rc = {10, 10, 50, 50};
m_btn.Create(m_hWnd, rc, "", WS_CHILD | WS_VISIBLE);
m_btn.ShowWindow(SW_SHOW);

But I'm using a CView class to display the button, not a CDialog. Is that a problem?

If I want a button to be visible "on" a CView client area, where would I call m_btn.ShowWindow(SW_SHOW)?

Thx,

/Tommy

Re: WTL - dynamically creating buttons etc.

Christian Graus2-Aug-01 11:35

Christian Graus

2-Aug-01 11:35

I'm not sure how ( or why ) you'd put a button onto a normal CView.

I am actually using the Windows Template Library, but to put buttons onto a CView in MFC, you can use a CFormView, which allows you to set them up using a dialog template.

Christian

#include "std_disclaimer.h"

The careful application of terror is also a form of communication.

Eagles may soar, but weasels don't get sucked into jet engines.

Re: WTL - dynamically creating buttons etc.

Michael Dunn31-Jul-01 20:06

Michael Dunn

31-Jul-01 20:06

We covered this topic a while ago in this thread Smile | :)

--Mike--
http://home.inreach.com/mdunn/
"Make sure that if you are using a blow torch that you don't set anything on fire."
-- Chris Maunder

Re: WTL - dynamically creating buttons etc.

Christian Graus1-Aug-01 2:59

Christian Graus

1-Aug-01 2:59

Um... not quite. There you (very helpfully) showed me how to hook up buttons and so on into a message map. Now I want to create them dynamically, not by putting them on a dialog template and calling SubclassWindow, but by having a vector of controls to which I can dynamically add them, and have the code able to respond to their being pushed. The idea is that we create a set of classes by which people can script the creation of a dialog box and it's controls, so it needs to be ultra flexible.

I've worked out that I can respond to OnCommand, and the lParam ( from memory, the code is at work and I am not ) is the HWND of the control, but none of the other paramters seen to contain anything meaningful. Is this the way to capture buttons I've created on the fly, and if so, does OnCommand respond to anything but controls being pushed ? Either way, when I have a lot of different elements on the dialog, I'm not sure how I'm going to be able to figure out what was interacted with and how, in order to respond to it meaningfully. The Create method didn't seem to take an ID I could assign, for example, and I'm trying not to think about intercepting messages on a dynamically created listview, for example.

Any suggestions you may have on how to deal with a variable number of controls on a dialog that will not be known until runtime will be greatly appreciated.

Christian

#include "std_disclaimer.h"

The careful application of terror is also a form of communication.

Eagles may soar, but weasels don't get sucked into jet engines.

Re: WTL - dynamically creating buttons etc.

Michael Dunn1-Aug-01 13:06

Michael Dunn

1-Aug-01 13:06

Ah, gotcha, I see what you're asking now. Smile | :)

Here's a snippet that creates a button at runtime. This came from the CP toolbar, actually, and creates an edit box on the toolbar.

  // m_wndToolbar is a CContainedWindow<ATLControls::CToolBarCtrl>
  // m_wndSearchEdit is a CContainedWindowT<ATLControls::CEdit>
 
    m_wndToolbar.GetItemRect ( 1, &rect );
 
DWORD dwEditStyle = WS_CHILD | WS_VISIBLE | WS_TABSTOP | WS_BORDER | ES_AUTOHSCROLL;
DWORD dwEditExStyle = WS_EX_CLIENTEDGE;
HWND hwndEditbox = CreateWindowEx ( dwEditExStyle,  _T("EDIT"), _T(""), dwEditStyle,
                                    rect.left+5, rect.top, rect.right - rect.left-10,
                                    rect.bottom - rect.top, m_wndToolbar,
                                    (HMENU) uSearchEditboxID, NULL, 0 );
 
    m_wndSearchEdit.Attach ( hwndEditbox );

This uses member variables for the windows (CContainWindow objects) but this would work equally well for objects you create at runtime.

As for your WM_COMMAND question - lParam is the HWND of the button, HIWORD(wParam) is BN_CLICKED (which is 0), and LOWORD(wParam) is the button control ID. If wParam is coming in as 0, I'd say double-check the control IDs in your CreateWindow() or analogous calls.

--Mike--
http://home.inreach.com/mdunn/
"Make sure that if you are using a blow torch that you don't set anything on fire."
-- Chris Maunder

Re: WTL - dynamically creating buttons etc.

Christian Graus1-Aug-01 13:09

Christian Graus

1-Aug-01 13:09

Gotcha - thanks for the help.

Christian

#include "std_disclaimer.h"

The careful application of terror is also a form of communication.

Eagles may soar, but weasels don't get sucked into jet engines.

Create a Setup File

sankar31-Jul-01 16:10

sankar

31-Jul-01 16:10

There's a main project which consists of many VC & VB components as sub projects . Now I need to build a package which gives me an option to install these components by selecting them from the various options of the components - the installation of one of the componenets need to be in the remote machine. How can i do this???

Pl. suggest me some topics to get an idea on this.

Thanx.

regards
Sankar

dynamic_cast and void *

31-Jul-01 11:22

Can someone please point out to me what I am missing.

I have a number of classes (Stored Procedures) derived from a base class (CRecordset). The base class has functionality common to all the derived classes (Open, Execute, Close fuctions), so I am trying to create a function where I can pass the object to operate on as a pointer to the base class, find the derived class from the RTTI and call the appropriate functions.

However my problem is that the compiler sees the void * from the dynamic_cast and complains when I try and call members associated with a void *. I can see why this would be a problem, the compiler has no information on the object pointed to by the void *, after all this is only available at runtime, but is there anyway around this problem?

I wondered if I could use pointers to members to create offsets into the class, but again the compiler complains that the left side of the argument points to a void *.

I believe what I am trying to do can be done, I'm just not sure what I am missing.

Thanks,

Richard

Re: dynamic_cast and void *

Ben Burnett31-Jul-01 14:07

Ben Burnett

31-Jul-01 14:07

Correct me if I'm wrong, but could you not use the base class instead of void to declare your pointers?

Ben Burnett

---------
On the topic of code with no error handling -- It's not poor coding, it's "optimistic" Wink | ;)

Re: dynamic_cast and void *

Asif Ahmad31-Jul-01 19:57

Asif Ahmad

31-Jul-01 19:57

Here's how to use dynamic_cast. Supposing CMyRecordset is derived from CRecorset.

void somefunc()
{
CMyRecordset objMyRecordset;
CRecordset* pRecordset;
pRecordset = dynamic_cast<CRecordset*>(&objMyRecordset);
if (pRecordset)
{
pRecordset->Open(); //or whatever...
}
}

Good Luck,
Asif

Re: dynamic_cast and void *

Malcolm McMahon31-Jul-01 22:59

Malcolm McMahon

31-Jul-01 22:59

It's not clear why you're using void * in this context, or, for that matter, why you can't do whatever it is you're trying to do with virtual methods.

dynamic_cast is generally used for up-casting, that is casting something stored in the routine as a pointer to a more generic class to a more specific class (which it must actually be). It should very rarely be needed. You could do something like:

<br />
GeneralClass *p = ......<br />
<br />
SpecificClass *sp = dynamic_class<SpecificClass *>p;<br />
<br />
if(sp) { // this actually is an instance of SpecificClass<br />
...<br />
  }<br />

but it's almost always cleaner to do the same thing with virtual methods.

CCtrlView does not show my items

Wim Jans31-Jul-01 11:05

Wim Jans

31-Jul-01 11:05

Hello,

I've created an MDI application based on a CCtrlView.

After that, I copied some code of msdn to create 2 header columns and some list data.
The problem is that I can see the header, but not the data. I know there is data in the grid because if I double click on the small | in the header, the header resizes as if there is data.

Is it due to the fact that the text is also drawn in a white color, or am I doing something wrong here (forgot to initialize something, call a procedure, ... ).

Some info;

In PreCreateWindow I set my style in detail view:
cs.style |= LVS_REPORT

In OnInitialUpdate, I try to create the 'grid':

CListView::OnInitialUpdate();

// this code only works for a report-mode list view
ASSERT(GetStyle() & LVS_REPORT);

CListCtrl& theCtrl = GetListCtrl();
// Insert a column. This override is the most convenient.
theCtrl.InsertColumn(0, _T("Player Name"), LVCFMT_LEFT);
LVCOLUMN col;
col.mask = LVCF_FMT | LVCF_TEXT;
col.pszText = _T("Jersey Number");
col.fmt = LVCFMT_LEFT;
theCtrl.InsertColumn(1, &col);
// Set reasonable widths for our columns
theCtrl.SetColumnWidth(0, LVSCW_AUTOSIZE_USEHEADER);
theCtrl.SetColumnWidth(1, LVSCW_AUTOSIZE_USEHEADER);

for (int i=0;i < 10;i++)
{
strText.Format(TEXT("item %d"), i);

// Insert the item, select every other item.
theCtrl.InsertItem(
LVIF_TEXT|LVIF_STATE, i, strText,
(i%2)==0 ? LVIS_SELECTED : 0, LVIS_SELECTED,
0, 0);

// Initialize the text of the subitems.
for (int j=1;j < nColumnCount;j++)
{
strText.Format(TEXT("sub-item %d %d"), i, j);
theCtrl.SetItemText(i, j, strText);
}
}

Confused | :confused:

Thanks a lot

Wim Jans

Re: CCtrlView does not show my items

Ben Burnett31-Jul-01 14:24

Ben Burnett

31-Jul-01 14:24

Works fine for me, exept I just had to add in two lines (in bold bellow)

// --> CListView::OnInitialUpdate();<br />
<br />
// this code only works for a report-mode list view<br />
ASSERT(GetStyle() & LVS_REPORT);<br />
<br />
CListCtrl& theCtrl = GetListCtrl();<br />
// Insert a column. This override is the most convenient.<br />
theCtrl.InsertColumn(0, _T("Player Name"), LVCFMT_LEFT);<br />
LVCOLUMN col;<br />
col.mask = LVCF_FMT | LVCF_TEXT;<br />
col.pszText = _T("Jersey Number");<br />
col.fmt = LVCFMT_LEFT;<br />
theCtrl.InsertColumn(1, &col);<br />
// Set reasonable widths for our columns<br />
theCtrl.SetColumnWidth(0, LVSCW_AUTOSIZE_USEHEADER);<br />
theCtrl.SetColumnWidth(1, LVSCW_AUTOSIZE_USEHEADER);<br />
<br />
for (int i=0;i < 10;i++)<br />
{<br />
strText.Format(TEXT("item %d"), i);<br />
<br />
// Insert the item, select every other item.<br />
theCtrl.InsertItem(<br />
LVIF_TEXT|LVIF_STATE, i, strText, <br />
(i%2)==0 ? LVIS_SELECTED : 0, LVIS_SELECTED,<br />
0, 0);<br />
<br />
CString strText;<br />
int nColumnCount = theCtrl.GetHeaderCtrl()->GetItemCount();<br />
<br />
// Initialize the text of the subitems.<br />
for (int j=1;j < nColumnCount;j++)<br />
{<br />
strText.Format(TEXT("sub-item %d %d"), i, j);<br />
theCtrl.SetItemText(i, j, strText);<br />
}<br />
}

Ben Burnett

---------
On the topic of code with no error handling -- It's not poor coding, it's "optimistic" Wink | ;)

Re: CCtrlView does not show my items

Wim Jans1-Aug-01 2:12

Wim Jans

1-Aug-01 2:12

The code in Bold was actualy in my view, I only forgot to copy/paste it in Blush | :O

The form I was testing with uses the BCG library but I've just created an normal MDI mfc program based on CListView, copied the code and it worked fine indeed.

After that, I installed the new version of the BCG library and copied the code over to the view, and guess what: the list appeared. Big Grin | :-D

So, I think I will upgrade my library at home too and I can continue to try to get a grip of Visual C++ - which is a lot easier thanks to CodeProject.

Thanks for your time!

Wim

Extracting features from a BMP

Russel Hawkins31-Jul-01 10:57

Russel Hawkins

31-Jul-01 10:57

Has anyone got experiance with extracting features from a bitmap image. Cool | :cool:

Re: Extracting features from a BMP

C^hris L^osinger31-Jul-01 11:18

C^hris L^osinger

31-Jul-01 11:18

what do you mean by "features" ?

-c

------------------------------
Smaller Animals Software, Inc.
http://www.smalleranimals.com

Re: Extracting features from a BMP

Russel Hawkins31-Jul-01 21:36

Russel Hawkins

31-Jul-01 21:36

Yes I guess my question was rather broad.

What I have is two finger print bitmaps that I would like to compare the connection points to. This is not generalized graphics but rather a science of forensics.

There are books available on the subject, there seems to be no code guidelines available on who to do this in C++.

Can you help.
Cool | :cool:

Reading int/long lengths from binary file

31-Jul-01 10:08

Sorry to ask again but how do I read INTEGER or LONG length values in from a binary file?
At the moment I can only get single bytes.
Do I use GET or READ?
How to I modify the following code to read an integer length value from address 4110 in the DAT file?

==============================================

ofstream path("c:\\windows\\desktop\\debug.dat");
........................

int pos = 4110;
path.seekg(pos);
int bytevalue = path.get();

================================================

Sorry to be dumb, tried to work it out myself but failed (& no online helpfile)

cheers
Richard Edwards

Re: Reading int/long lengths from binary file

Paolo Messina31-Jul-01 10:45

Paolo Messina

31-Jul-01 10:45

Hi,

I'm not sure, since I don't often use C++ streams to do I/O, but it seems you should use: path.read((char*)&myInt, 4); if you're using ifstream.

Paolo

------
"airplane is cool, but space shuttle is even better" (J. Kaczorowski)

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