Thread: Looping through the windows registry using RegEnumKeyEx till the leaves

Hi all,

I am trying to write code to loop through the windows registry till i find the leaf , meaning the
key value pair exists . Each time i get the key , i want to know whether it is parent of some key-value pair.
If yes , loop through its children till the point where a key comes which has no child. I tried writing the program on my own
using RegEnumKeyEx , The key structure is given below.

If you type "regedit", you get the following template...

Code:

	System
	   Select
		Current - 2
		Default - "Key"
		Known	- "Key2"
		LastError - "Key"
	   Select1
		Current - 2
		Default - "Key"
		Known	- "Key2"
		LastError - "Key"
	   Select2
		Current - 2
		Default - "Key"
		Known	- "Key2"
		LastError - "Key"

In the above tree , i want to loop through subkeys of "System" like Select , Select1 and Select2
and loop through the key value pair as given above.I have written the code as below for retrieving
subkeys.

Code:

void QueryKey(HKEY hKey) 
{ 
    TCHAR    achKey[500];   // buffer for subkey name
    DWORD    cbName;                   // size of name string 
    TCHAR    achClass[MAX_PATH] = TEXT("");  // buffer for class name 
    DWORD    cchClassName = MAX_PATH;  // size of class string 
    DWORD    cSubKeys=0;               // number of subkeys 
    DWORD    cbMaxSubKey;              // longest subkey size 
    DWORD    cchMaxClass;              // longest class string 
    DWORD    cValues;              // number of values for key 
    DWORD    cchMaxValue;          // longest value name 
    DWORD    cbMaxValueData;       // longest value data 
    DWORD    cbSecurityDescriptor; // size of security descriptor 
    FILETIME ftLastWriteTime;      // last write time 
 
    DWORD i, retCode; 
 
    TCHAR  achValue[MAX_VALUE_NAME]; 
    DWORD cchValue = MAX_VALUE_NAME; 
 
    // Get the class name and the value count. 
    retCode = RegQueryInfoKey(
        hKey,                    // key handle 
        achClass,                // buffer for class name 
        &cchClassName,           // size of class string 
        NULL,                    // reserved 
        &cSubKeys,               // number of subkeys 
        &cbMaxSubKey,            // longest subkey size 
        &cchMaxClass,            // longest class string 
        &cValues,                // number of values for this key 
        &cchMaxValue,            // longest value name 
        &cbMaxValueData,         // longest value data 
        &cbSecurityDescriptor,   // security descriptor 
        &ftLastWriteTime);       // last write time 
 
    // Enumerate the subkeys, until RegEnumKeyEx fails.
    
    if (cSubKeys)
    {
        printf( "\nNumber of subkeys: %d\n", cSubKeys);
		if(cSubKeys!=0)
        for (i=0; i<cSubKeys; i++) 
        { 
            cbName = MAX_KEY_LENGTH;
            retCode = RegEnumKeyEx(hKey, i,
                     achKey, 
                     &cbName, 
                     NULL, 
                     NULL, 
                     NULL, 
                     &ftLastWriteTime); 
            if (retCode == ERROR_SUCCESS) 
            {
                _tprintf(TEXT("(%d) %s\n"), i+1, achKey);

            }
		//Here write a recursive function to loop through the subkeys
        }
    
	} 
	else
	{
		printf("This is a child\n");
	}
 
    // Enumerate the key values. 

    }
}

What problem are you having?