Creating a WHOIS Lookup Client

For your convenience, here is the entire code for the program, all in one place.

unit main;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics,
Controls, Forms,
  Dialogs, StdCtrls, ExtCtrls, IdTCPConnection, IdTCPClient,
IdWhois,
  IdBaseComponent, IdComponent, IdTCPServer, IdWhoIsServer,
IdDNSResolver,
  IdCustomTCPServer, ComCtrls, Buttons;
type
  TForm1 = class(TForm)
    Panel2: TPanel;
    IdWhoIsServer1: TIdWhoIsServer;
    IdWhois1: TIdWhois;
    IdDNSResolver: TIdDNSResolver;
    Panel3: TPanel;
    Panel4: TPanel;
    hname: TEdit;
    cb: TComboBox;
    Panel5: TPanel;
    g_info: TBitBtn;
    StaticText1: TStaticText;
    StaticText2: TStaticText;
    Memo1: TMemo;
    lv: TListView;
    hostnme: TEdit;
    StaticText3: TStaticText;
    resolve: TBitBtn;
    StatusBar1: TStatusBar;
    dns: TEdit;
    StaticText4: TStaticText;
    StaticText5: TStaticText;
    procedure g_infoClick(Sender: TObject);
    procedure resolveClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
    li:tlistitem;
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.g_infoClick(Sender: TObject);
begin
memo1.Clear;
//label1.Caption:='Connected';

 with IdWhois1 do begin
    Host :=cb.text;
    memo1.Lines.Text := whois(trim(hname.text));
 end;

//idWhois1.Disconnect;

end;

procedure TForm1.resolveClick(Sender: TObject);
var
  Count:     Integer;
  DNSServer: String;
  HostName:  String;
  I:         Integer;
begin
  Memo1.Lines.Clear;
  DNSServer:=dns.Text;
  HostName:=hostnme.Text;
  if (DNSServer='')or(HostName='') then
  begin
    Memo1.Lines.Add('*** Error ***');
    if DNSServer='' then
      Memo1.Lines.Add('DNS Server is empty.');
    if HostName='' then
      Memo1.Lines.Add('Host name is empty.');
    Exit;
   end;
  IdDNSResolver.Host:=DNSServer;
   IdDNSResolver.QueryType:=[qtA];
 IdDNSResolver.Resolve(HostName);
  Count:= IdDNSResolver.QueryResult.Count;
  if Count=0 then Exit;
  for I:=0 to Count-1 do
  begin
        if  IdDNSResolver.QueryResult.Items[I] is TARecord then
    li:=lv.Items.Add;
      with TARecord( IdDNSResolver.QueryResult[I]) do   begin
       //Memo1.Lines.Add(ClassName+': '+Name+' resolves to IP
address '+IPAddress);
      li.Caption:=Name;
    li.SubItems.Add(IPaddress);
    end;
    end;
   end;
end.