Convert unicode string into wchar_t - winapi

Question

I'm having a little problem with my application while trying to use WindowsAPI...
I'm trying to connect to a handle in a way it works, but if I change the code it doesn't works anymore...
The code that works:
handle_t porta; // Global var
COMMTIMEOUTS tempos; // Global var
DCB configuracao; // Global var
wchar_t pcCommPort[]= TEXT("COM1");
//gate address to be accessed (COM1)
The code I'm trying to do:
handle_t porta; // Global var
COMMTIMEOUTS tempos; // Global var
DCB configuracao; // Global var
String GATE = "COM" + Label1->Text;
wchar_t pcCommPort[]= TEXT(GATE);
//gate address to be accessed (Any gate)
I've also tried it:
handle_t porta; // Global var
COMMTIMEOUTS tempos; // Global var
DCB configuracao; // Global var
wchar_t pcCommPort[]= TEXT("COM" + Label1->Text);
//gate address to be accessed (Any gate)
And it:
handle_t porta; // Global var
COMMTIMEOUTS tempos; // Global var
DCB configuracao; // Global var
String GATE = "COM" + Label1->Text;
wchar_t pcCommPort[]= GATE;
//gate address to be accessed (Any gate)
In any way or it says that I haven't mede the correct syntax or the error: Cannot convert unicode string into a wchar_t.
EDIT:
Full source (function):
void abrirporta(){
wchar_t pcCommPort[]= TEXT("COM1");
//endereço da porta a ser acessada (COM1)
//porta foi declarado como HANDLE na seção private da declaração de classe Form
//HANDLE porta
porta = CreateFile(pcCommPort,GENERIC_READ+GENERIC_WRITE,0,NULL,OPEN_EXISTING,0,NULL);
if(porta == INVALID_HANDLE_VALUE){
log(7);
throw Exception("Não foi possível abrir a porta COM.\nPor favor, tente novamente!");
}
//Tempo máximo entre o recebimento de 2 bytes (ms)
tempos.ReadIntervalTimeout = 20;
//Multiplicador de tempo de recebimento por byte
tempos.ReadTotalTimeoutMultiplier = 0;
tempos.ReadTotalTimeoutConstant = 100;
tempos.WriteTotalTimeoutMultiplier = 0;
tempos.WriteTotalTimeoutConstant = 100;
if(!SetCommTimeouts(porta ,&tempos))
{
CloseHandle(porta);
frmPrincipal->spLig->Visible = False;
frmPrincipal->spStatusInd->Visible = False;
log(6);
throw Exception("Erro na configuração de Timeout");
}
GetCommState(porta, &configuracao);
configuracao.BaudRate = 19200;
configuracao.ByteSize = 8;
configuracao.Parity = NOPARITY;
configuracao.StopBits = ONESTOPBIT;
if(!SetCommState(porta,&configuracao))
{
CloseHandle(porta);
frmPrincipal->spLig->Visible = False;
frmPrincipal->spStatusInd->Visible = False;
log(5);
throw Exception("Erro na Configuração da porta");
}
frmPrincipal->spLig->Visible = True;
frmPrincipal->spStatusInd->Visible = False;
log(3);
frmPrincipal->btEnviar->Enabled = true;
frmPrincipal->swSaida1->Enabled = true;
log(8);
}
I hope you can help me...
Since now thanks XD.

Answer 1

You are making this more difficult then it needs to be. System::String is an alias for System::UnicodeString, which holds wchar_t data on Windows. You don't need to copy the UnicodeString data into a wchar_t[] buffer. You can use the UnicodeString::c_str() method when you need to pass a String to a function that expects wchar_t* parameters, eg:
void abrirporta()
{
String pcCommPort = L"COM" + Label1->Text;
porta = CreateFile(pcCommPort.c_str(), ...);
...
}