C#

// ValidateSN.cpp : Defines the entry point for the DLL application.<br />
//<br />
<br />
#include "stdafx.h"<br />
#include <tchar.h><br />
#include <stdlib.h><br />
#include "ValidateSN.h"<br />
<br />
BOOL APIENTRY DllMain( HANDLE hModule, <br />
                       DWORD  ul_reason_for_call, <br />
                       LPVOID lpReserved<br />
					 )<br />
{<br />
    return TRUE;<br />
}<br />
<br />
LONG WINAPI ValidateSN(HWND hwnd, LPSTR szSrcDir, LPSTR szSupport, LPSTR szSerialNum, LPSTR szDbase)<br />
{<br />
	//Check for proper length<br />
	if (_tcslen( szSerialNum ) != SERIALNUMBER_LENGTH)<br />
	{<br />
		#ifdef _DEBUG //Display Debug information<br />
			MessageBox(GetFocus(), "Serial Key is Invalid!", "Validation Failed", MB_OK);		<br />
		#endif<br />
		return VALIDATION_FAILED;<br />
	}<br />
<br />
	//Copy serial number to temp variable before parsing<br />
	TCHAR szTemp[255];<br />
	_tcscpy(szTemp, szSerialNum);<br />
<br />
<br />
	//Get individual fields of the serial number (tokens separated by '-' chracter)<br />
	LPSTR szField1 = _tcstok( szTemp, TOKEN_SEPERATOR );<br />
    LPSTR szField2 = _tcstok( NULL, TOKEN_SEPERATOR );<br />
    LPSTR szField3 = _tcstok( NULL, TOKEN_SEPERATOR );<br />
<br />
	#ifdef _DEBUG  //Display Debug information<br />
		CHAR szTmp[1024];<br />
		wsprintf(szTmp, "szSerialNum=%s. \nField #1=%s \nField #2=%s \nField #3=%s", szSerialNum, szField1, szField2, szField3);<br />
//MessageBox(GetFocus(), szTmp, "Serial Number Debug Window", MB_OK);<br />
	#endif<br />
<br />
	//Validate three fields in this example<br />
	if (ValidateField1(szField1) != VALIDATION_SUCCESS)<br />
	{<br />
		#ifdef _DEBUG //Display Debug information<br />
	MessageBox(GetFocus(), "Serial Key is Incorrect!", "Validation Failed!", MB_OK);		<br />
		#endif<br />
<br />
		return VALIDATION_FAILED;<br />
	}<br />
	else if (ValidateField2(szField2) != VALIDATION_SUCCESS)<br />
	{<br />
		#ifdef _DEBUG //Display Debug information<br />
	MessageBox(GetFocus(), "Serial Key is Incorrect!", "Validation Failed!", MB_OK);		<br />
		#endif<br />
<br />
	    return VALIDATION_FAILED;<br />
	}<br />
	else if (ValidateField3(szField3) != VALIDATION_SUCCESS)<br />
	{<br />
		#ifdef _DEBUG //Display Debug information<br />
	MessageBox(GetFocus(), "Serial Key is Incorrect!", "Validation Failed!", MB_OK);		<br />
		#endif<br />
<br />
		return VALIDATION_FAILED;<br />
	}<br />
	else<br />
		return VALIDATION_SUCCESS;<br />
}<br />
<br />
LONG ValidateField1(LPSTR szField1)<br />
{<br />
	//First field must be the string 'Field1'<br />
	if (_tcsicmp (szField1, SERIALNUM_FIELD1) == 0)<br />
	{<br />
		return 1;<br />
	}<br />
	else<br />
		return -1;<br />
}<br />
<br />
LONG ValidateField2(LPSTR szField2)<br />
{<br />
<br />
	long lNumToValidate = atoi (szField2);<br />
<br />
	//Second field must be a multiple of 5<br />
	if ((lNumToValidate % 3) == 0)<br />
		return VALIDATION_SUCCESS;<br />
	else <br />
		return VALIDATION_FAILED;<br />
}<br />
<br />
LONG ValidateField3(LPSTR szField3)<br />
{<br />
	//Don't do anything - accept all values in third field<br />
	return VALIDATION_SUCCESS;<br />
<br />
}