如何得到局域网内机器上当前的用户名？(50分)

如何得到局域网内机器上当前的用户名，我想做个类似netscan的东西。

http://www.csdn.net/cnshare/soft/16/16699.shtm

如下程序获得当前工作组中的所以计算机：
unit Unit1;

interface

uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls, ExtCtrls;

type
TForm1 = class(TForm)
Button1: TButton;
Memo1: TMemo;
Edit1: TEdit;
StaticText1: TStaticText;
Panel1: TPanel;
procedure Button1Click(Sender: TObject);
procedure FormCreate(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;

Function GetUsers(GroupName:string;var List:TStringList):Boolean;

implementation
{$R *.DFM}
type
TNetResourceArray = ^TNetResource; //网络资源类型的数组

Function GetUsers(GroupName:string;var List:TStringList):Boolean;
Var
NetResource:TNetResource;
Buf : Pointer;
Count,BufSize,Res : DWord;
Ind : Integer;
lphEnum : THandle;
Temp:TNetResourceArray;
Begin
Result := False;
List.Clear;
FillChar(NetResource, SizeOf(NetResource), 0); //初始化网络层次信息
NetResource.lpRemoteName := @GroupName[1]; //指定工作组名称
NetResource.dwDisplayType := RESOURCEDISPLAYTYPE_SERVER;//类型为服务器（工作组）
NetResource.dwUsage := RESOURCEUSAGE_CONTAINER;
NetResource.dwScope := RESOURCETYPE_DISK; //列举文件资源信息
Res := WNetOpenEnum( RESOURCE_GLOBALNET, RESOURCETYPE_DISK,RESOURCEUSAGE_CONTAINER, @NetResource,lphEnum);
If Res <> NO_ERROR Then Exit; //执行失败
While True Do //列举指定工作组的网络资源
Begin
Count := $FFFFFFFF; //不限资源数目
BufSize := 8192; //缓冲区大小设置为8K
GetMem(Buf, BufSize);//申请内存，用于获取工作组信息,获取计算机名称
Res := WNetEnumResource(lphEnum, Count, Pointer(Buf), BufSize);
If Res = ERROR_NO_MORE_ITEMS Then break;//资源列举完毕
If (Res <> NO_ERROR) then Exit;//执行失败
Temp := TNetResourceArray(Buf);
For Ind := 0 to Count - 1 do//列举工作组的计算机名称
Begin
List.Add(Temp^.lpRemoteName);
Inc(Temp);
End;
End;
Res := WNetCloseEnum(lphEnum);//关闭一次列举
If Res <> NO_ERROR Then exit;//执行失败
Result:=True;
FreeMem(Buf);
end;

procedure TForm1.Button1Click(Sender: TObject);
var
List:TstringList;
i:integer;
begin
try
List:=TstringList.Create;
if GetUsers(edit1.text,List) then
if List.count=0 then //工作组下没找到计算机
begin
memo1.Lines.Add (edit1.text+'工作组下没有计算机！');
end
else
memo1.Lines.Add (edit1.text+'下的所有计算机如下：');
for i:=0 to List.Count-1 do
begin
Memo1.lines.Add (List.strings);
end;
finally
List:=TstringList.Create; //如有异常则释放分配的资源
end;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
memo1.Lines.Clear ;
end;


end.

如下程序检测局域网中某台机器是否在网上
在edit1.text中输入计算机名。

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls,Winsock;

type
TForm1 = class(TForm)
Button1: TButton;
Edit1: TEdit;
StaticText1: TStaticText;
Memo1: TMemo;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;

function FindComputer(ComputerName: string):Boolean;

implementation

{$R *.DFM}

function FindComputer(ComputerName: string):Boolean;
var
WSAData: TWSAData;
HostEnt: PHostEnt;
begin
Result :=True;
WSAStartup(2, WSAData);
HostEnt := gethostbyname(PChar(ComputerName));
if HostEnt = nil then Result := False;
WSACleanup;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
if FindComputer(edit1.text)=True then
Memo1.lines.Add(edit1.text+'在局域网上！')
else
Memo1.lines.Add(edit1.text+'不在局域网上！');
end;

end.

多人接受答案了。