C / C++ / MFC

Rage29-Jan-03 21:38

Rage

29-Jan-03 21:38

I'll just expand what Himanshu said :

First get a control to the button you want to active. Two ways to do it :
1.Add a control with the class wizard, let's name it m_FirstButton.
In the CMyDlg::OnInitDialog()

BOOL CMyDlg::OnInitDialog()
{
...stuff...
m_FirstButton.SetCheck(TRUE);
...stuff...
}

_or_

2.Get a control to it through the Index (IDC_...), like following :

BOOL CMyDlg::OnInitDialog()
{
...stuff...
CButton *firstbutton=(CButton*)GetDlgItem(IDC_FIRSTRADIOBUTTON);
firstbutton->SetCheck(TRUE);
...stuff...
}

And as Himanshu said, you can do some calculation also in the InitInstance (like processing the command line) if this is needed to chose which of your radiobutton should be active at startup.

~RaGE();

rohit.dhamija29-Jan-03 21:50

rohit.dhamija

29-Jan-03 21:50

GetDlgItem is giving errors
CButton *firstbutton=(CButton*)GetDlgItem(IDC_FIRSTRADIOBUTTON);firstbutton->SetCheck(TRUE);

Eek! | :eek:

GetDlgItem' : function does not take 1 parameters
Error executing cl.exe.

jhwurmbach29-Jan-03 22:07

jhwurmbach

29-Jan-03 22:07

Use a control-variable. You can make those with the Wizard, exactly like the Member variable, but you have to set the type to 'Control'.
Now, you have all options that the respective MFC-class offers.

Especially handy as your dialog grows.

My opinions may have changed, but not the fact that I am right.

Abbas_Riazi29-Jan-03 21:57

Abbas_Riazi

29-Jan-03 21:57

Just set your radio button member variable in dialog constructor. e.g.:

if your member variable is m_Options:

CDummyDlg::CDummyDlg()
{
	//{{{AFX_...
	m_Options = 0;	//first option, changed from m_Options=-1;
	//}}}AFX_...
}

A. Riazi

rohit.dhamija29-Jan-03 22:07

rohit.dhamija

29-Jan-03 22:07

Good Riazi that really worked !!! Big Grin | :-D

Delete History of Internet?

Rage29-Jan-03 23:02

Rage

29-Jan-03 23:02

Sorry, i had not thought that you could have used the value associated to your button (i prefer using controls). Riazi got me on this one. Poke tongue | ;-P

~RaGE();

xxhimanshu29-Jan-03 20:18

xxhimanshu

29-Jan-03 20:18

Hi all,
I want to delete the history, cache entries and cookies craeted by internet thru programming..Is there any good tutorial or can anyone guide me so as how to do it...Any thoughts and ideas are most welcome..
Thanks in advance..

Himanshu

Re: Delete History of Internet?

Abbas_Riazi29-Jan-03 22:08

Abbas_Riazi

29-Jan-03 22:08

Just call some shell function to retrieve folders of Temprory Internet Files and also History then delete all of files on it!
For more information on how to retrieve shell folders path, view my article: System Information[^].
A. Riazi

Re: Delete History of Internet?

Rohit Sinha30-Jan-03 1:51

Rohit Sinha

30-Jan-03 1:51

Take a look at this article:

http://www.codeproject.com/shell/surfhelper.asp[^]

Regards,

Rohit Sinha

Re: Delete History of Internet?

xxhimanshu30-Jan-03 2:02

xxhimanshu

30-Jan-03 2:02

thanks buddy..this was what I was looking for....thans a lot..
cheers

Himanshu

Encryption/Decryption

Zaid Ansari29-Jan-03 19:28

29-Jan-03 19:28

i am using CALG_MD5 to encrypt/decrypt a string. it encryts the text but in decrypting it shows error "NTE_BAD_DATA" on lastblock other blocks are decrypted well. How can i resolve this erro.
Note:
final parameter is set to true for last block.

karl_w29-Jan-03 21:39

karl_w

29-Jan-03 21:39

Zaid Ansari wrote:
am using CALG_MD5 to encrypt/decrypt a string

Are you sure you are using MD5 for encyrption/decryption? MD5 is an hash-algorithm so its result can't be "decrypted". Search the net for information about hashing vs. encrypting/decrypting. You could use algorithms like AES or DES for your needs.

--

karl

Zaid Ansari29-Jan-03 22:03

29-Jan-03 22:03

thanks karl,
i know that MD5 is a one way hash but i dont have any experiance in VC can u please tell me if i am making any mistake in this code.

to //code
if(!CryptAcquireContext(&hCryptProv, NULL, NULL, PROV_RSA_FULL,0))
{
}
// Create a hash object.
if(!CryptCreateHash(hCryptProv, CALG_MD5, 0, 0, &hHash))
{
strcat(strErrorMessage, "Error executing CryptCreateHash");
return NULL;
}

if(!CryptHashData(hHash, (BYTE *)password, strlen(password), 0))
{
strcat(strErrorMessage, "Error executing CryptHashData");
return NULL;
}
// Derive a session key from the hash object.
if(!CryptDeriveKey(hCryptProv, CONST_ENCRYPT_ALGORITHM, hHash, 0, &hKey))
{
strcat(strErrorMessage, "Error executing CryptDeriveKey");
return NULL;
}

// Destroy the hash object.
CryptDestroyHash(hHash);
hHash = 0;

// Determine number of bytes to encrypt at a time.
// This must be a multiple of CONST_ENCRYPT_BLOCK_SIZE.
// CONST_ENCRYPT_BLOCK_SIZE is set by a #define statement.
dwBlockLen = 10 - 10 % CONST_ENCRYPT_BLOCK_SIZE;
// get data block as close to 1000 bytes as possible making sure it's a multiple of ENCRYPT_BLOCK_SIZE

// Determine the block size. If a block cipher is used,
// it must have room for an extra block.
if(CONST_ENCRYPT_BLOCK_SIZE > 1)
dwBufferLen = dwBlockLen + CONST_ENCRYPT_BLOCK_SIZE;
else
dwBufferLen = dwBlockLen;

// Allocate memory.
pbBuffer = (BYTE *)malloc(dwBufferLen);
BYTE *pAllBlocks = NULL;
BYTE *pPreviousBlocks = NULL;
bool fMoreDataExists = true;
DWORD dwIndex = 0;
DWORD dwLength;
DWORD dwLengthOfEncryptedData;
DWORD dwAllBlocksLength, dwPreviousBlocksLength;

// Make way through data one block at a time. Find out how big
// each encrypted string will be, allocate memory for it, and save
// in array.
do
{
// get next block of clear text data
GetBYTEDataBlockFromString(dwIndex, pClearTextString, dwBlockLen, pbBuffer, dwLength);
// check if more data exists after current block

if (dwIndex >= strlen(pClearTextString))
fMoreDataExists = false;

// encrypt current data block
dwLengthOfEncryptedData = dwLength;
if(!CryptEncrypt(hKey, 0, !fMoreDataExists, 0, pbBuffer, &dwLengthOfEncryptedData, dwBufferLen))
{
fout<<"Error Occured in CryptEncrypt";
}
if (pAllBlocks)
delete [] pAllBlocks;
if (pPreviousBlocks)
dwAllBlocksLength = dwPreviousBlocksLength + dwLengthOfEncryptedData;
else
dwAllBlocksLength = dwLengthOfEncryptedData;

pAllBlocks = new BYTE[dwAllBlocksLength];
if (!pAllBlocks)
{
if(pbBuffer)
free(pbBuffer);
if (pPreviousBlocks)
delete [] pPreviousBlocks;
strcat(strErrorMessage, "Unable to allocate memory for pAllBlocks");
FreeAllCryptHandles(hKey, hHash, hCryptProv);
return NULL;
}
// copy all encrypted data to pAllBlocks

if (pPreviousBlocks)
{
CopyBYTEData(dwPreviousBlocksLength, pPreviousBlocks, pAllBlocks, dwAllBlocksLength, 0);
CopyBYTEData(dwLengthOfEncryptedData, pbBuffer, pAllBlocks, dwAllBlocksLength, dwPreviousBlocksLength);
delete [] pPreviousBlocks;
}
else
CopyBYTEData(dwLengthOfEncryptedData, pbBuffer, pAllBlocks, dwAllBlocksLength, 0);

if (fMoreDataExists)
{ // save previous data blocks for next iteration of this do loop
dwPreviousBlocksLength = dwAllBlocksLength;
pPreviousBlocks = new BYTE[dwPreviousBlocksLength];
if (!pPreviousBlocks)
{
if(pbBuffer)
free(pbBuffer);
if (pAllBlocks)
delete [] pAllBlocks;
strcat(strErrorMessage, "Unable to allocate memory for pPreviousBlocks");
FreeAllCryptHandles(hKey, hHash, hCryptProv);
return NULL;
}
else
CopyBYTEData(dwAllBlocksLength, pAllBlocks, pPreviousBlocks, dwPreviousBlocksLength, 0);
}
}
while(fMoreDataExists);

Zaid Ansari29-Jan-03 22:05

29-Jan-03 22:05

can any one send me code for encryption/decryption string using DES.

karl_w30-Jan-03 0:08

karl_w

30-Jan-03 0:08

It's not DES, but it uses the Windows-CryptAPI.
On the other hand I'm quite sure there is a class outside in the wild which provides DES-encryption.

	<br />
HCRYPTPROV hCryptProv;<br />
HCRYPTKEY hKey;<br />
HCRYPTHASH hHash;<br />
<br />
if ( !CryptAcquireContext(&hCryptProv, NULL , NULL, PROV_RSA_FULL,  0))<br />
    AfxMessageBox("Error Acquire");<br />
<br />
if ( !CryptCreateHash(hCryptProv, CALG_MD5, 0, 0, &hHash))<br />
    AfxMessageBox("Error CreateHash");<br />
<br />
if ( !CryptHashData(hHash, (BYTE*) "YourKey", (DWORD)strlen("YourKey"), 0))<br />
    AfxMessageBox("Error Hashing");<br />
<br />
if ( !CryptDeriveKey(hCryptProv, CALG_RC4, hHash, 0, &hKey))<br />
    AfxMessageBox("Error Derive Key");<br />
<br />
BYTE* buf; //The thing you want to encrypt<br />
DWORD size = (DWORD)strlen((char*)buf);<br />
     <br />
CryptEncrypt(hKey, NULL, TRUE, 0, (BYTE*)buf, &size, size);<br />
<br />
CryptDecrypt(hKey, NULL, TRUE, 0, (BYTE*)buf, &size)<br />
<br />

This works fine for me. It's not a high-security app, so i hardcoded the encryption-key in the code. I simply took the Class-Name as key.

Hope I could help.

--

karl

Zaid Ansari30-Jan-03 0:46

30-Jan-03 0:46

i need simple DES encryption / decryption with hardcoded key. Thanks a lot Karl i will try this.

Zaid Ansari3-Feb-03 5:02

3-Feb-03 5:02

Thanks a lot Mr.Karl, it worked but now i have data which contanis 300 character but it encrypts forst 56 characters only. can u please tell me how can i do this both encryption and decryption.

karl_w3-Feb-03 6:28

karl_w

3-Feb-03 6:28

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/security/Security/cryptencrypt.asp

--

karl

Zaid Ansari3-Feb-03 20:19