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I've tried putting the following code in the MainFrame, the MDIChildWnd and the View with no luck:
CWnd* prnt = (CWnd*)::GetDesktopWindow();
if(prnt)
this->SetParent(prnt);
The actual create code is buried in the MFC DocView architecture somewhere - I don't know what method can be overriden to try to pass in the desktop window as the parent.
Maybe someone can help with that?
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This is just a guess, but usually a parent window will clip any child window. Possibly you need to override the PreCreate of the MDI Parent and change it's attributes so as not to clip children.
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Hi everybody.
I have a problem with Serial Communication in MFC. My program could not open serial port and the error is INVALID_HANDLE_VALUE. But if I open the Hyper Terminal program before opening my program, my code is running and I had succeed open port and read port operations. I can't understand this situation.
Thanks in advance...
Port settings are like these (These are parameters)
Baud Rate : 9600
Parity : Even
Stop Bits : 1
Data Bits : 7
And the scale is connected COM1 port to the computer.
My simple code is below as:
////////////////////////////
dcb.DCBlength=sizeof(DCB);
dcb.BaudRate=(unsigned long)atol(m_sBaudRate);
if ( m_sParity.Compare("None") == 0 )
dcb.Parity = NOPARITY;
else
if ( m_sParity.Compare("Even") == 0 )
dcb.Parity = EVENPARITY;
else
if ( m_sParity.Compare("Odd") == 0 )
dcb.Parity = ODDPARITY;
else
dcb.Parity = NOPARITY;
.........
.........
hComm = CreateFile(m_sCOM /*COM1*/,
GENERIC_READ | GENERIC_WRITE,
0,
/* comm devices must be opened w/exclusive-access */ NULL,
/* no security attrs */ OPEN_EXISTING,
/* comm devices must use OPEN_EXISTING */ 0,
/* not overlapped I/O */ NULL /* hTemplate must be NULL for comm devices */ );
if (hComm == INVALID_HANDLE_VALUE)
{
AfxMessageBox("Port not opened!");
}
..............................
..............................
ReadData(m_sResults);
///////////////////////////////////////////////////////////
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Why are you setting DCB values before actually open the communication port?
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
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I tried to set DCB properties after calling CreateFile(..) method but it didn't work. 
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sahanaskin wrote: if (hComm == INVALID_HANDLE_VALUE)
{
AfxMessageBox("Port not opened!");
}
Did it ever occur to you to call GetLastError() here?
"Love people and use things, not love things and use people." - Unknown
"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne
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sahanaskin wrote: Yes, getlasterror returns 1,
Which equates to ERROR_INVALID_FUNCTION.
"Love people and use things, not love things and use people." - Unknown
"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne
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I'm sorry; I had wrote returning value incorrect, GetLastError() returns 0 in my program.
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Well, if CreateFile() is returning INVALID_HANDLE_VALUE and GetLastError() is returning 0, I don't know what to tell you.
"Love people and use things, not love things and use people." - Unknown
"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne
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Yes, exactly same as you said 
Thanks anyway.
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Has suggested by David Crow the two conditions should be mutually exclusive. Please, clean the code and try again.
(Try also the classical MSDN sample code [^]).
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
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Other than the first argument (he doesn't indicate what value m_sCOM has, only what the comment shows), his call to CreateFile() looks identical.
"Love people and use things, not love things and use people." - Unknown
"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne
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I changed some part of my code. Now, I wrote GetLastError section like belove and the getlasterror result was 6:
hComm_ = CreateFile("COM1", // Specify port device: default "COM1"
GENERIC_READ | GENERIC_WRITE, // Specify mode that open device.
0, // the devide isn't shared.
NULL, // the object gets a default security.
OPEN_EXISTING, // Specify which action to take on file.
0, // default.
NULL); // default.
// Get current configuration of serial communication port.
if (GetCommState(hComm,&dcb) == 0)
{
char sMsg[512];
DWORD dwError = GetLastError();
sprintf(sMsg, "Error=%d ",
dwError);
AfxMessageBox(sMsg); // prints to screen 6
return FALSE;
}
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And dcb variable has these attributes (I set them in constructor):
dcb.ByteSize = 7;
dcb.StopBits = ONESTOPBIT;
dcb.Parity = EVENPARITY;
dcb.BaudRate = CBR_9600;
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sahanaskin wrote: ...the getlasterror result was 6:
Which equates to ERROR_INVALID_HANDLE.
"Love people and use things, not love things and use people." - Unknown
"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne
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Am I wrong to call CreateFile(..) method code section or what? When does The ERROR_INVALID_HANDLE error happen? please help me I'm confused?
hComm_ = CreateFile("COM1", // Specify port device: default "COM1"
GENERIC_READ | GENERIC_WRITE, // Specify mode that open device.
0, // the devide isn't shared.
NULL, // the object gets a default security.
OPEN_EXISTING, // Specify which action to take on file.
FILE_FLAG_OVERLAPPED, // default.
NULL); // default.
// Get current configuration of serial communication port.
if (GetCommState(hComm, &dcb) == 0)
......
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sahanaskin wrote: When does The ERROR_INVALID_HANDLE error happen?
This happens when CreateFile() fails. Your CreateFile is probably returning INVALID_HANDLE_VALUE.
As has been previously stated, you need to call GetLastError() to see why this is occuring. Modify your code as follows:
hComm_ = CreateFile("COM1",
GENERIC_READ | GENERIC_WRITE,
0,
NULL,
OPEN_EXISTING,
FILE_FLAG_OVERLAPPED,
NULL);
if(INVALID_HANDLE_VALUE == hComm_)
{
DWORD dwErr = GetLastError();
LPTSTR lpMsgBuf = NULL;
FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,NULL,dwErr,MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),(LPTSTR) &lpMsgBuf,0,NULL);
TRACE(_T("ERROR: %s\n"),lpMsgBuf);
LocalFree(lpMsgBuf);
}
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Yes, I suggest him to use the MSDN sample as it stands, without preliminary stuff.
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
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Hi,
MSDN tells us this:
--COM ports
--The CreateFile function can create a handle to a COM port. By setting the dwCreationDisposition
--parameter to OPEN_EXISTING, read-only, write-only, or read/write access can be specified
But I did not successed to open port. If I open the hyper terminal program only one time, and then i closed hyper terminal ; this code works and serial_handle is not equal invalid.. :
if (serial_handle!=INVALID_HANDLE_VALUE)
CloseHandle(serial_handle);
serial_handle = INVALID_HANDLE_VALUE;
serial_handle = CreateFile("COM1",GENERIC_READ | GENERIC_WRITE,
0, NULL, OPEN_EXISTING ,NULL,NULL);
if ( serial_handle == INVALID_HANDLE_VALUE )
{
GetLastError(); // it returns 0
I couldn't understand this situation? Please tell me where am I wrong?
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Why do you preventively close the handle? Why don't you copy the MSDN sample as it stands (possibly changing the port string) and try?
BTW Could you please post the routine complete code?
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
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My method is this:
/************************************************************************************************/
void CDlgComPortConnectTest::OpenPort()
{
//if (serial_handle!=INVALID_HANDLE_VALUE)
// CloseHandle(serial_handle);
//serial_handle = INVALID_HANDLE_VALUE;
serial_handle = CreateFile( m_sCOM /*"COM1"*/,
GENERIC_READ | GENERIC_WRITE,
0, /* comm devices must be opened w/exclusive-access */
NULL, /* no security attrs */
OPEN_EXISTING, /* comm devices must use OPEN_EXISTING */
NULL, /* not overlapped I/O */
NULL /* hTemplate must be NULL for comm devices */ );
if (GetCommState(serial_handle,&dcb) == 0)
{
char sMsg[512];
DWORD dwError = GetLastError();
sprintf(sMsg, "Error=%d ",dwError);
AfxMessageBox(sMsg);
AfxMessageBox(GetLastError());
AfxMessageBox("Get configuration port has problem.");
return;
}
FillMemory(&dcb, sizeof(dcb), 0);
dcb.DCBlength = sizeof(dcb);
dcb.BaudRate=(unsigned long)atol(m_sBaudRate);//(unsigned long)(9600);
if ( m_sParity.Compare("None") == 0 )
dcb.Parity = NOPARITY;
else
if ( m_sParity.Compare("Even") == 0 )
dcb.Parity = EVENPARITY;
else
if ( m_sParity.Compare("Odd") == 0 )
dcb.Parity = ODDPARITY;
else
dcb.Parity = NOPARITY;
if ( m_sStopBits.Compare("1") == 0 )
dcb.StopBits = ONESTOPBIT;
else
if ( m_sStopBits.Compare("1.5") == 0 )
dcb.StopBits = ONE5STOPBITS;
else
if ( m_sStopBits.Compare("2") == 0 )
dcb.StopBits = TWOSTOPBITS;
else
dcb.StopBits = ONESTOPBIT;
if ( m_sDataBits.Compare("7") == 0 )
dcb.ByteSize = 7;
else
if( m_sDataBits.Compare("8") == 0 )
dcb.ByteSize = 8;
else
dcb.ByteSize = 8;
dcb.fAbortOnError = TRUE;
if (serial_handle == INVALID_HANDLE_VALUE)
{
CString sDC;
sDC.Format("B_commopen = FALSE;\n%d, %d, %d, %d", dcb.XonChar, dcb.XoffChar, dcb.XonLim, dcb.XoffLim);
AfxMessageBox(sDC);
B_commopen = FALSE;
char sMsg[512];
DWORD dwError = GetLastError();
sprintf(sMsg, "Error=%d ",
dwError);
AfxMessageBox(sMsg);
ASSERT(FALSE);
// error opening port; abort
}
else
{
B_PortReady = SetupComm(serial_handle, 128, 128); // set buffer sizes
B_commopen = TRUE;
}
Read(m_sResults);
}
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You're testing the handle value in the wrong place. You should test it immediately after the CreateFile call (failure), otherwise you'll not get meaningful info by GetLastError (other function calls reset last error). Moreover it doesn't make any sense calling GetCommState with an invalid handle as argument.
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
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Thanks for your advice. I wrote the function as you said and GetLastError function returned 5 (ACCESS DENIED), how I solve this error?
:
/************************************************************************************************/
void CDlgComPortConnectTest::OpenPort()
{
//if (serial_handle!=INVALID_HANDLE_VALUE)
// CloseHandle(serial_handle);
//serial_handle = INVALID_HANDLE_VALUE;
serial_handle = CreateFile( m_sCOM /*"COM1"*/,
GENERIC_READ | GENERIC_WRITE,
0, /* comm devices must be opened w/exclusive-access */
NULL, /* no security attrs */
OPEN_EXISTING, /* comm devices must use OPEN_EXISTING */
NULL, /* not overlapped I/O */
NULL /* hTemplate must be NULL for comm devices */ );
if (serial_handle == INVALID_HANDLE_VALUE)
{
B_commopen = FALSE;
char sMsg[512];
DWORD dwError = GetLastError();
sprintf(sMsg, "Error=%d ",
dwError);
AfxMessageBox(sMsg);
ASSERT(FALSE);
// error opening port; abort
}
if (GetCommState(serial_handle,&dcb) == 0)
{
char sMsg[512];
DWORD dwError = GetLastError();
sprintf(sMsg, "Error=%d ",dwError);
AfxMessageBox(sMsg);
AfxMessageBox(GetLastError());
AfxMessageBox("Get configuration port has problem.");
return;
}
FillMemory(&dcb, sizeof(dcb), 0);
dcb.DCBlength = sizeof(dcb);
dcb.BaudRate=(unsigned long)atol(m_sBaudRate);//(unsigned long)(9600);
if ( m_sParity.Compare("None") == 0 )
dcb.Parity = NOPARITY;
else
if ( m_sParity.Compare("Even") == 0 )
dcb.Parity = EVENPARITY;
else
if ( m_sParity.Compare("Odd") == 0 )
dcb.Parity = ODDPARITY;
else
dcb.Parity = NOPARITY;
if ( m_sStopBits.Compare("1") == 0 )
dcb.StopBits = ONESTOPBIT;
else
if ( m_sStopBits.Compare("1.5") == 0 )
dcb.StopBits = ONE5STOPBITS;
else
if ( m_sStopBits.Compare("2") == 0 )
dcb.StopBits = TWOSTOPBITS;
else
dcb.StopBits = ONESTOPBIT;
if ( m_sDataBits.Compare("7") == 0 )
dcb.ByteSize = 7;
else
if( m_sDataBits.Compare("8") == 0 )
dcb.ByteSize = 8;
else
dcb.ByteSize = 8;
dcb.fAbortOnError = TRUE;
B_PortReady = SetupComm(serial_handle, 128, 128); // set buffer sizes
B_commopen = TRUE;
}
Read(m_sResults);
}
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That means the serial port is currently owned by another application.
Have you closed the hyperterminal?
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
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