Wix: Add to Listbox from C++ Custom Action

Question

Hi i'm trying to check the COM Ports on a users machine and then insert them into a listbox via a custom action in c++. Although it is not displaying the information and when I debug all it is saying is "Function Failed To Execute" This is my Wix code for the listbox:

       <Control Id="ListBoxID" Type="ListBox" Property="COMPORT" Width="80" Height="40" X="80" Y="165" Indirect="no">
      <ListBox Property="COMPORT">
      </ListBox>
      <Condition Action="hide">(DEVICETYPE = "1")</Condition>
      <Condition Action="show">(DEVICETYPE = "2")</Condition>
      <Condition Action="show">(DEVICETYPE = "3")</Condition>
      <Condition Action="hide">(DEVICETYPE = "4")</Condition>
    </Control>

And this is my Custom Action:

extern "C" UINT __stdcall GetDatascanPort(MSIHANDLE hInstall)
{

HRESULT hr = S_OK;
UINT er = ERROR_SUCCESS;
HKEY keyHandle;
DWORD i,openStatus,cb_value_buffer,cb_buffer,dwType;
char value_buffer[100],buffer[10];
MSIHANDLE hTable = NULL;
MSIHANDLE hColumns = NULL;
MSIDBERROR insertError = MSIDBERROR_NOERROR; 

hr = WcaInitialize(hInstall, "GetDatascanPort");
ExitOnFailure(hr, "Failed to initialize");

WcaLog(LOGMSG_STANDARD, "Initialized.");


if (RegCreateKeyEx( HKEY_LOCAL_MACHINE,
                    "HARDWARE\\DEVICEMAP\\SERIALCOMM",
                    0,
                    "",
                    REG_OPTION_NON_VOLATILE,
                    KEY_QUERY_VALUE,
                    default_sa(),
                    &keyHandle,
                    &openStatus )  == ERROR_SUCCESS )
{
    for (i=0;;i++)
    {
        cb_value_buffer = sizeof(value_buffer);
        cb_buffer = sizeof(buffer);

        if (RegEnumValue(keyHandle,
                         i,
                         value_buffer,
                         &cb_value_buffer,
                         NULL,
                         &dwType,
                         (unsigned char *) buffer,
                         &cb_buffer) != ERROR_SUCCESS)
                         break;

        if (dwType != REG_SZ || strlen(buffer) > 6)
            continue;

        hr = WcaAddTempRecord(&hTable, &hColumns, L"ListBox",&insertError, 0, 4, L"COMPORT", 1, 0, buffer);
        ExitOnFailure(hr, "failed to set COMPORT"); 


    }

    RegCloseKey(keyHandle);

    if (hTable)
        MsiCloseHandle(hTable);
    if (hColumns)
        MsiCloseHandle(hColumns);
    return WcaFinalize(hr);

}

LExit:
er = SUCCEEDED(hr) ? ERROR_SUCCESS : ERROR_INSTALL_FAILURE;
return WcaFinalize(er);
}

Can anyone help me please? Thanks

EDIT: I have it updating my Listbox but it is not legible, strange symbols. I changed my char to a CString like so and this seems to work apart from displaying it incorrectly.

CString ComPort;
    ComPort = buffer;

hr = WcaAddTempRecord(&hTable, &hColumns, L"ListBox",&insertError, 0, 4, L"COMPORT", 1, ComPort, ComPort);
ExitOnFailure(hr, "failed to set COMPORT"); 

Also the target computer may have serial ports what is the best method to have them all listed with my function inside the for loop?

Thanks

Answer 1

Got it working. This is the code I amended incase it may help others:

        MultiByteToWideChar(CP_ACP,0,buffer,-1,ComPort,strlen(buffer));
        ComPort[strlen(buffer)]=0;

        hr = WcaAddTempRecord(&hTable, &hColumns, L"ListBox",&insertError, 0, 4, L"COMPORT", value++, ComPort, ComPort);
        ExitOnFailure(hr, "failed to set COMPORT");

Thanks to @snowdude I knew I had to convert the char to Wide Char.