RegSetValueEx does not set in unicode project build - c++

Question

I'm trying to write data to registry, but it always writes foreigner language instead because the setvalue is "MyApp"
CStringA temp(setvalue);//setvalue is CString type
const BYTE* pData = (const BYTE*)(LPCSTR)temp;
lResult = RegSetValueEx(hKey, path, NULL, REG_SZ, (LPBYTE)pData, sizeof(pData));
RegCloseKey(hKey);
if(lResult == ERROR_SUCCESS || lResult == ERROR_MORE_DATA)
return true;
else
return false;
thanks.

Answer 1

The way you are converting CString to BYTE* is causing the problem. No need of using CStringA.
Try this conversion of CString to TCHAR. This should work
LPTSTR lpszData = new TCHAR[setvalue.GetLength()+1]; // setvalue is CString type...
_tcscpy(lpszData , csTemp);
lResult = RegSetValueEx(hKey, path, NULL, REG_SZ, (LPBYTE)lpszData, setvalue.GetLength()+1);
delete[] lpszData;// don't forget to do this.

Answer 2

Try RegSetValueExA(). You are calling a function which is expecting unicode strings. the A() function takes ANSI args

Answer 3

Any Win32 API function that accepts TCHAR, LPTSTR or LPCTSTR parameters will accept either Ansi or Unicode data depending on whether the UNICODE conditional is defined during compiling (RTL functions like _tcscpy use the _UNICODE conditional instead). So what's really happening in this case is that when you call RegSetValueEx() in your code, it gets resolved by the compiler to either calling RegSetValueExA() (Ansi) or RegSetValueExW() (Unicode) depending on the UNICODE conditional.
The CStringA class is for Ansi data only. You have to convert its data to Unicode when calling RegSetValueExW().
To do what you are attempting, you need to either:
1) call RegSetValueExA() explicitally instead of RegSetValueEx() generically if you contiinue using the CStringA class:
CStringA temp(setvalue);
lResult = RegSetValueExA(hKey, path, NULL, REG_SZ, (LPBYTE)(LPSTR)temp, (temp.GetLength() + 1) * sizeof(CHAR));
2) Use the CString class instead of the CStringA class. CString is based on TCHAR, so it is also influenced by the UNICODE conditional, and thus matches the format that RegSetValuEx() is expecting:
CString temp(setvalue);
lResult = RegSetValueEx(hKey, path, NULL, REG_SZ, (LPBYTE)(LPTSTR)temp, (temp.GetLength() + 1) * sizeof(TCHAR));
In the latter case, if your setvalue variable is already a CString, then just use it as-is, no need to create a temp copy of it:
lResult = RegSetValueEx(hKey, path, NULL, REG_SZ, (LPBYTE)(LPTSTR)setvalue, (setvalue.GetLength() + 1) * sizeof(TCHAR));