Re: Still need help with FTPConnection - C / C++ / MFC Discussion Boards

Johniteq15-Aug-06 4:27

15-Aug-06 4:27

I have a problem related to a window that in some cases owns a context/popup menu.
Here is the code for the creation and tracking of the popup menu:

LRESULT
MyWindowClass::OnCreateAndTrackPopupMenu(UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL& bHandled)
{
HMENU aMenu = ::LoadMenu(_Module.GetResourceInstance(),(LPCTSTR)IDR_CONTEXT_MENU);

    if(aMenu != NULL)
    {
      HMENU hSubMenu = ::GetSubMenu(aMenu,0);
      if(hSubMenu != NULL)
      {
        SetForegroundWindow(m_hWnd);
        TrackPopupMenuEx(hSubMenu,TPM_LEFTALIGN|TPM_TOPALIGN,pt.x,pt.y,m_hWnd,NULL);
        ::PostMessage(m_hWnd, WM_NULL, 0, 0); 
      }
      ::DestroyMenu(aMenu);
    }
  return 0;
}

My application response to a window message that should deal with the destruction of the window above:

LRESULT
MyMainClass::OnDestroyWindow(UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL& bHandled)
{
  ::PostMessage(MyWindowClass->m_hWnd,WM_CANCELMODE,0,0);
  MyWindowClass->DestroyWindow();
  delete MyWindowClass;
  MyWindowClass= NULL;
  return 0;
}

The problem: If the popup menu is present when the destruction (DestroyWindow()) takes place, the application will crash ("ERROR - Object deleted before window was destroyed"), because the popup menu still is active (still waiting for TrackPopupMenuEx() to return because WM_CANCELMODE never reach the window before it is destroyed).

So the question is, how can I make sure that the OnCreateAndTrackPopupMenu-function return before DestroyWindow() is executed?

john

Re: Destroying window with popup menu

Maximilien15-Aug-06 4:59

Maximilien

15-Aug-06 4:59

you can do something like :

You call DestroyWindow ( to delete the Window object ), this will eventually call PostNcDestroy, in which you will do a delete this, to delete the C++ object,and before that, send a message ( SendMessage ) to the caller of the window to set its pointer to NULL.

For example :

void MyAutoDeleteDialog::PostNcDestroy() 
{
  BaseDialog::PostNcDestroy();

  // this will send a message and will set the pointer to the object to NULL.
  AfxGetMainWnd()->SendMessage( WM_AUTO_DELETE_DIALOG_CLOSED, 0, 0 );

  // delete the C++ object.
  delete this;
}

Maximilien Lincourt
Your Head A Splode - Strong Bad

Re: Destroying window with popup menu

Johniteq16-Aug-06 1:37

Johniteq

16-Aug-06 1:37

Thanx for the quick response. I understand your solution and what it does, but it doesn't seem like it solves my problem. I need to cancel the dialog before the object is deleted by using WM_CANCELMODE. How does this fit into the solution?

john

Re: Destroying window with popup menu

Michael Dunn15-Aug-06 13:12

Michael Dunn

15-Aug-06 13:12

Try SendMessage instead of PostMessage

--Mike--
Visual C++ MVP Cool | :cool:

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Re: Destroying window with popup menu

Johniteq16-Aug-06 1:42

Johniteq

16-Aug-06 1:42

This doesn't do it for some reason. Maybe WM_CANCELMODE IS received synchronically, but TrackPopupMenu() never returns anyhow, before it is too late and the object is deleted - crash Dead | X|

.

john

Still need help with FTPConnection

racing5715-Aug-06 4:20

racing57

15-Aug-06 4:20

Hi Everyone, i am still having troule with this over a wan... can anyone shed any light on it for me ?? i am getting kinda desperate now !!

CFtpConnection Thread......

Thanks in advance

Lee

Re: Still need help with FTPConnection

includeh1015-Aug-06 6:49

includeh10

15-Aug-06 6:49

try to find sample programs in VC disks (MSDN).
FTP is very easy.

Re: Still need help with FTPConnection

racing5715-Aug-06 10:50

racing57

15-Aug-06 10:50

i have done... and the way i have written it works on the local network, but i have a router set up with 3-5 pcs on it and am using port forwarding, if i leave the ftp port at 21 it works fine, if i change the port to anything else i can connect and create folders etc, but cannot do file searches or transfer files... i need to have it on different port as i have upto 5 pcs to forward to...

please help....

Re: Still need help with FTPConnection

thangnvhl15-Aug-06 21:53

thangnvhl

15-Aug-06 21:53

Open your MSDN -> choose Index tab -> Type: FTP Sessions -> Enter

Sincerely
Thangnvhl

Re: Still need help with FTPConnection

racing5715-Aug-06 23:00

racing57

15-Aug-06 23:00

my problem isnt how to use msdn, as i have been programming for 6+ years.. and have used it a fair amount in that time... i have downloaded some sameple programs from this site and they all have the same problem....

Re: Still need help with FTPConnection

Justin Tay16-Aug-06 2:23

Justin Tay

16-Aug-06 2:23

are you forwarding your data port as well?

Re: Still need help with FTPConnection

racing5716-Aug-06 3:46

racing57

16-Aug-06 3:46

i dont know what port the data port is... can i set this up ?? if i use port 21 it works ok...

Re: Still need help with FTPConnection

Justin Tay16-Aug-06 22:01

Justin Tay

16-Aug-06 22:01

Here[^] is a decent explanation.

timers without windows

m.dietz15-Aug-06 4:09

m.dietz

15-Aug-06 4:09

Hi,

In a current project I need a class that monitors some maintenance data and regularly writes them to a log file. As this class is used in different modules in different ways, the functions should be encapsulated as best as possible and the usual way of using this class should be by giving a filename to the constructor to configure the instance and then calling Collect() to immediately collect and log the data or calling EnableTimer(time_span) to regularly log the data to the log file every time_span milliseconds.

The problem I can't solve is the timer. My first approach was

<br />
<br />
BOOL CMaintMonitor::EnableTimer(UINT interval)<br />
{<br />
    if(bl_TimerEnabled) StopTimer();<br />
    bl_TimerEnabled = TRUE;<br />
    ui_TimerInterval = interval;<br />
    TimerID = SetTimer(NULL, 0, interval, TimerFunction);<br />
    if(!TimerID)<br />
    {<br />
        bl_TimerEnabled = FALSE;<br />
        ui_TimerInterval = 0;<br />
        return FALSE;<br />
    }<br />
    return TRUE;<br />
}<br />
<br />
...<br />
<br />
BOOL CMaintMonitor::StopTimer()<br />
{<br />
    if(bl_TimerEnabled)<br />
    {<br />
        bl_TimerEnabled = FALSE;<br />
        ui_TimerInterval = 0;<br />
        KillTimer(TimerID);<br />
    }<br />
    return TRUE;<br />
}<br />

TimerFunction was thought as a private method of CMaintMonitor that calls Collect(). Visual C++ didn't like this approach, telling me that it couldn't convert parameter 4 of SetTimer from void(...) to void(__stdcall *)(...). Reading the help pages again I saw that this function is meant to send a WM_TIMER message to a window whose message processing function should call the provided function instead of standard functions, so it still needs a WM_TIMER message processing even if the window handle provided is NULL Confused | :confused:

.

The problem now is that I can't call a global function (I think this is what the compiler wants to say with the (__stdcall *) part of the error message) as Collect is a member function of an instance of CMaintMonitor using instance member data to do its work. So even if I found a way to use a global function for that timer event, I still need a way to give a pointer to my CMaintMonitor instance to that function for the call to Collect(), but I don't see a way to do so.

Can anyone help me solving the problem with that timer? This class should come without a user-Interface, so there is no window I can abuse to handle the timer event, and I can't even use the window of a caller as there are a lot of modules which come without UI either but still need to to use my monitor class. I'm new to programming under Windows, so I don't know if there might be an easy workaround for this problem I just don't know.

Thanks in advance
Martin Dietz

Re: timers without windows

led mike15-Aug-06 4:26

led mike

15-Aug-06 4:26

Take a look at the Win32 Timer Queue API[^]

led mike

Re: timers without windows

m.dietz15-Aug-06 5:07

m.dietz

15-Aug-06 5:07

This looks interesting, but I can't find it in my helppages and my compiler doesn't find it neither although I included windows.h (as said in the MSDN article), is it available in Visual C++ 6.0 (sorry I forgot to mention that I'm pinned to that compiler)?

Greetings
Martin

Re: timers without windows [modified]

led mike15-Aug-06 5:53

led mike

15-Aug-06 5:53

I was using it with VC6 a few years ago. You need to download the latest SDK from MSDN and make sure to include the header and library file paths in the IDE setup.

[modified] That is "Platform SDK" sorry

led mike

Last modified: Tuesday, August 15, 2006 10:50:44 AM -- Platform SDK

Re: timers without windows

m.dietz15-Aug-06 20:24

m.dietz

15-Aug-06 20:24

Sorry, but if I have to download something I'm not sure other developers in my company have installed, it's useless. I can't bring up a solution that can only be compiled on my computer. Sniff | :^)

Thanks anyway, I'll try if I can make sense of the Multimedia Timers cje mentioned
Martin

Re: timers without windows

led mike16-Aug-06 5:05

led mike

16-Aug-06 5:05

m.dietz wrote:
I'm new to programming under Windows

The Windows Platform SDK is a standard part of the operating system and any development environment. You should not be developing without it. You might want to do some reading about things life safe strings etc.

led mike

Re: timers without windows

cje15-Aug-06 4:26

cje

15-Aug-06 4:26

could you use using multi-media timers? There are articles here on code project that talk about them. I use a class that wraps the multimedia timer that I inherit from (MMTimer) that allows me to get an Update callback when the timer fires.

cje

Singleton problem !!!

Bratu Aurelian15-Aug-06 4:05

Bratu Aurelian

15-Aug-06 4:05

Hello!

I've implemented a singleton class and i discovered that in every .dll that i accessed a instance of the singleton a new instance is created. So, in every dll i have a different instance. My question is :How can I have a single instance of the singleton between multiple dll ?

This is my implementation:

class cSingleton
{
private:
static cSingleton* m_instance;

cSingleton(){};
~cSingleton(){};

public:
static cSingleton& Instance();
};

cSingleton& cSingleton::Instance()
{
if(m_instance == NULL)
{
m_instance = new cSingleton;
}
return *m_instance;
};

Thanks!

-- modified at 3:33 Thursday 17th August, 2006

Getting IP of a Network group PC

Kharfax15-Aug-06 4:03

Kharfax

15-Aug-06 4:03

Hi people

How can I get the IP of a machine in my workgroup?
I get a list of connected PCs in the workgroup using NetServerEnum, so I have the computer Name

Thanks in advance

Re: Getting IP of a Network group PC

David Crow15-Aug-06 4:09

David Crow

15-Aug-06 4:09

Kharfax wrote:
How can I get the IP of a machine in my workgroup?

Use gethostbyname().

"Money talks. When my money starts to talk, I get a bill to shut it up." - Frank

"Judge not by the eye but by the heart." - Native American Proverb

Re: Getting IP of a Network group PC

Kharfax15-Aug-06 4:11

Kharfax

15-Aug-06 4:11

Fantastic, thanks a lot David, that was a quick answer Big Grin | :-D

Re: Getting IP of a Network group PC

A_Fa15-Aug-06 19:45

A_Fa

15-Aug-06 19:45

void GetLocalIPAddress(char *ipAddress)
{
#define MAX_NAME_LEN 65

WSADATA wsaData;
if ( WSAStartup( MAKEWORD( 2, 2 ), &wsaData ) == 0 )
{
char HostName[MAX_NAME_LEN];
struct in_addr *ptr;

gethostname (HostName,MAX_NAME_LEN);

hostent *host = gethostbyname(HostName);

if(host == NULL)
{
ipAddress = NULL ;
WSACleanup( );
return ;
}

ptr = (struct in_addr *)host->h_addr_list[0];

CString str;
str.Format("%d.%d.%d.%d",
ptr->S_un.S_un_b.s_b1,
ptr->S_un.S_un_b.s_b2,
ptr->S_un.S_un_b.s_b3,
ptr->S_un.S_un_b.s_b4);
strcpy(ipAddress,(char*)str.GetString());
}

WSACleanup( );
}

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