Occasionally, a user moves or deletes a file. To ensure that your program always has a working user interface, you can bind one set of language resources into the executable and use DLLs only for additional languages, or you can bind in a single error message telling the user that the user interface module is missing.

The sample code below searches for all possible language resources contained in both the current executable and possible DLL files and builds a list box that displays the possible user interface language choices to the user. It uses the FindFirstFile and FindNextFile API functions to search for DLLs named with three-letter ISO codes. Once the user selects a language, the program calls the LoadLanguage function described earlier to load the appropriate DLL. Both EnumResLangProc and EnumResourceLanguages are fully documented in the Windows API Quick Reference topics of the same names.

/////////////////////
// struct for use by MyFindAllLanguages and EnumResLangProc

typedef struct _tagLBData{ // list box data

HWND hWnd; // handle to window/dialog box
// containing the list box
int nListBox; // ID of the list box to fill
DWORD dwErrCode; // reason for failure of EnumResLangProc
} LBDATA, *PLBDATA;

#define NAMESTART 12 // offset to filename in list box item
// string (list box item strings will
// not be translated)

/////////////////////
// The following code will locate all the available languages for a
// resource, whether you are using resources in separate DLLs,
// resources in the EXE, or both. This example assumes that the DLLs
// follow the naming convention from the earlier example. With a
// sufficiently unique combination of resource name and type as a
// flag, you can search for your DLLs anywhere on the path.

BOOL CALLBACK EnumResLangProc(
HMODULE hModule, // resource-module handle
LPCTSTR lpszType, // address of resource type
LPCTSTR lpszName, // address of resource name
LANGID wIDLanguage, // resource language identifier
LPARAM lParam) // application-defined
// parameter
{
PLBDATA pLBData = (PLBDATA)lParam;
static TCHAR szItemText[NAMESTART + MAX_PATH];

// Display language ID components in the list box text. The
// format of the text will be: "PriLang SubLang - FileName".

wsprintf(szItemText, TEXT("%#02x %#02x - "),
PRIMARYLANGID(wIDLanguage),
SUBLANGID(wIDLanguage));

// Append the name of the file containing the resource.
if (0 < GetModuleFileName(hModule,
&szItemText[ lstrlen(szItemText) ],
MAX_PATH))
{
// Add the line to the list box.
SendDlgItemMessage(pLBData->hWnd, pLBData->nListBox,
LB_ADDSTRING, 0, (LPARAM)szItemText);
}
else
{ // Send reason for the failure of the call to GetModuleFileName
// back to our caller.
pLBData->dwErrCode = GetLastError();
}
// If this call failed, cause the enumeration process in
// EnumResourceLanguages to halt.
return (pLBData->dwErrCode == ERROR_SUCCESS ? TRUE : FALSE);
}

///////////////////////////
// MyFindAllLanguages
//
// Fill the given list box with the languages in which the given
// resource is available. This function will add the data to the
// given list box. No assumption is made about any of the list box's
// attributes (such as whether it is sorted). This function
// first empties the list box.
//
// MyFindAllLanguages returns ERROR_SUCCESS if successful or
// results of GetLastError() if unsuccessful.

DWORD MyFindAllLanguages(
HWND hWnd, // handle to window or dialog box
// containing the list box
int nListBox, // ID number of the list box to fill
LPCTSTR lpszType, // name or ID number of resource
// type to be enumerated
LPCTSTR lpszName) // name or ID number of resource
// name to be enumuerated
{
// Make sure the list box is empty.
SendDlgItemMessage(hWnd, nListBox, LB_RESETCONTENT, 0, 0);

LBDATA LBData;
LBData.hWnd = hWnd; // Fill in the LBData fields
LBData.nListBox = nListBox; // so the data gets sent to
// EnumResLangProc.

LBData.dwErrCode = ERROR_SUCCESS; // Assume we will be
// successful.

WIN32_FIND_DATA ffd; // for info from FindFirstFile and
// FindNextFile
HANDLE hFind = FindFirstFile(TEXT("???.DLL"), &ffd);

if (hFind != INVALID_HANDLE_VALUE)
{
do
{
HINSTANCE hModule = LoadLibraryEx(ffd.cFileName, hFind,
LOAD_LIBRARY_AS_DATAFILE);

if ( !EnumResourceLanguages(hModule, // Look in the DLL.
lpszType, // given resource type
lpszName, // given resource name
(ENUMRESLANGPROC) // address of
EnumResLangProc, // callback function
(LPARAM) &LBData) ) // application-defined
// parameter
{
LBData.dwErrCode = GetLastError();
}
FreeLibrary(hModule);
} while (LBData.dwErrCode == ERROR_SUCCESS &&
FindNextFile(hFind, &ffd) );

FindClose( hFind );
}
else
{
LBData.dwErrCode = GetLastError();
}

if (LBData.dwErrCode == ERROR_SUCCESS ||
LBData.dwErrCode == ERROR_FILE_NOT_FOUND )
{
LBData.dwErrCode = ERROR_SUCCESS;

if ( !EnumResourceLanguages( NULL, // Look in the current EXE.
lpszType, // given resource type
lpszName, // given resource name
(ENUMRESLANGPROC) // address of
EnumResLangProc, // callback function
(LPARAM) &LBData) ) // application-defined
{ // parameter
LBData.dwErrCode = GetLastError();
}
}
return (LBData.dwErrCode);
}