Function to return the MAC address of a remote or local machine in the format 'XX-XX-XX-XX-XX-XX'

返回的MAC地址是一个能用在多个方面的唯一标识。使用方法：
ShowMessage(GetMacAddress('\\MHEYDON');
输出'00-02-08-E7-99-6B'

// ======================================================================
//返回值是主机AServerName的MAC地址
//AServerName参数的格式为'\\ServerName' 或者 'ServerName'
//参数ServerName为空时返回本机的MAC地址
//MAC地址以'XX-XX-XX-XX-XX-XX'的格式返回
// ======================================================================

function GetMacAddress(const AServerName : string) : string;
type
TNetTransportEnum = function(pszServer : PWideChar;
Level : DWORD;
var pbBuffer : pointer;
PrefMaxLen : LongInt;
var EntriesRead : DWORD;
var TotalEntries : DWORD;
var ResumeHandle : DWORD) : DWORD; stdcall;

TNetApiBufferFree = function(Buffer : pointer) : DWORD; stdcall;

PTransportInfo = ^TTransportInfo;
TTransportInfo = record
quality_of_service : DWORD;
number_of_vcs : DWORD;
transport_name : PWChar;
transport_address : PWChar;
wan_ish : boolean;
end;

var E,ResumeHandle,
EntriesRead,
TotalEntries : DWORD;
FLibHandle : THandle;
sMachineName,
sMacAddr,
Retvar : string;
pBuffer : pointer;
pInfo : PTransportInfo;
FNetTransportEnum : TNetTransportEnum;
FNetApiBufferFree : TNetApiBufferFree;
pszServer : array[0..128] of WideChar;
i,ii,iIdx : integer;
begin
sMachineName := trim(AServerName);
Retvar := '00-00-00-00-00-00';

// Add leading \\ if missing
if (sMachineName <> '') and (length(sMachineName) >= 2) then begin
if copy(sMachineName,1,2) <> '\\' then
sMachineName := '\\' + sMachineName
end;

// Setup and load from DLL
pBuffer := nil;
ResumeHandle := 0;
FLibHandle := LoadLibrary('NETAPI32.DLL');

// Execute the external function
if FLibHandle <> 0 then begin
@FNetTransportEnum := GetProcAddress(FLibHandle,'NetWkstaTransportEnum');
@FNetApiBufferFree := GetProcAddress(FLibHandle,'NetApiBufferFree');
E := FNetTransportEnum(StringToWideChar(sMachineName,pszServer,129),0,
pBuffer,-1,EntriesRead,TotalEntries,Resumehandle);

if E = 0 then begin
pInfo := pBuffer;

// Enumerate all protocols - look for TCPIP
for i := 1 to EntriesRead do begin
if pos('TCPIP',UpperCase(pInfo^.transport_name)) <> 0 then begin
// Got It - now format result 'xx-xx-xx-xx-xx-xx'
iIdx := 1;
sMacAddr := pInfo^.transport_address;

for ii := 1 to 12 do begin
Retvar[iIdx] := sMacAddr[ii];
inc(iIdx);
if iIdx in [3,6,9,12,15] then inc(iIdx);
end;
end;

inc(pInfo);
end;
if pBuffer <> nil then FNetApiBufferFree(pBuffer);
end;

try
FreeLibrary(FLibHandle);
except
// 错误处理
end;
end;
result:=Retvar;
end;