nt, IdStack;
type
TUDPMainForm = class(TForm)
SourceGroupBox: TGroupBox;
HostNameLabel: TLabel;
HostAddressLabel: TLabel;
HostName: TLabel;
HostAddress: TLabel;
UDPAntiFreeze: TIdAntiFreeze;
PortLabel: TLabel;
Port: TLabel;
DestinationLabel: TLabel;
DestinationAddress: TLabel;
BufferSizeLabel: TLabel;
BufferSize: TLabel;
UDPMemo: TMemo;
SendButton: TButton;
UDPClient: TIdUDPClient;
procedure FormCreate(Sender: TObject);
procedure SendButtonClick(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
UDPMainForm: TUDPMainForm;
implementation
const
HOSTNAMELENGTH = 80;
RECIEVETIMEOUT = 5000; // milliseconds
{$R *.DFM}
procedure TUDPMainForm.FormCreate(Sender: TObject);
begin
Randomize; // remove if you want reproducible results.
HostName.Caption := UDPClient.LocalName;
HostAddress.Caption := GStack.LocalAddress;
Port.Caption := IntToStr(UDPClient.Port);
DestinationAddress.Caption := UDPClient.Host;
BufferSize.Caption := IntToStr(UDPClient.BufferSize);
UDPClient.ReceiveTimeout := RECIEVETIMEOUT;
end;
procedure TUDPMainForm.SendButtonClick(Sender: TObject);
var
MessageID: Integer;
ThisMessage: String;
ReceivedString: String;
begin
MessageID := Random(MAXINT);
ThisMessage := ''Message: '' + IntToStr(MessageID);
UDPMemo.Lines.Add(''Sending '' + ThisMessage);
UDPClient.Send(ThisMessage);
ReceivedString := UDPClient.ReceiveString();
if ReceivedString = '''' then
UDPMemo.Lines.Add(''No response received from the server after '' + IntToStr(UDPClient.ReceiveTimeout) + '' millseconds.'')
else
UDPMemo.Lines.Add(''Received: '' + ReceivedString)
end;
end.

--------------------------------------------------------------------------------

Notes:
Simple UDP server demo
Verified:
Indy 9:
D7: 25th Oct 2004 Andy Neillans
}
unit UDPServerMain;
interface
uses
Windows, Messages, Graphics, Controls, Forms, Dialogs, IdWinsock2, stdctrls,
SysUtils, Classes, IdBaseComponent, IdAntiFreezeBase, IdAntiFreeze,
IdComponent, IdUDPBase, IdUDPClient, IdStack, IdUDPServer, IdSocketHandle;
type
TUDPMainForm = class(TForm)
SourceGroupBox: TGroupBox;
HostNameLabel: TLabel;
HostAddressLabel: TLabel;
HostName: TLabel;
HostAddress: TLabel;
UDPServer: TIdUDPServer;
UDPAntiFreeze: TIdAntiFreeze;
PortLabel: TLabel;
Port: TLabel;
BufferSizeLabel: TLabel;
BufferSize: TLabel;
UDPMemo: TMemo;
procedure FormCreate(Sender: TObject);
procedure UDPServerUDPRead(Sender: TObject; AData: TStream; ABinding: TIdSocketHandle);
private
{ Private declarations }
public
{ Public declarations }
end;
var
UDPMainForm: TUDPMainForm;
implementation
const
HOSTNAMELENGTH = 80;
{$R *.DFM}
procedure TUDPMainForm.FormCreate(Sender: TObject);
begin
HostName.Caption := UDPServer.LocalName;
HostAddress.Caption := GStack.LocalAddress;
Port.Caption := IntToStr(UDPServer.DefaultPort);
BufferSize.Caption := IntToStr(UDPServer.BufferSize);
UDPServer.Active := True;
end;
procedure TUDPMainForm.UDPServerUDPRead(Sender: TObject; AData: TStream; ABinding: TIdSocketHandle);
var
DataStringStream: TStringStream;
s: String;
begin
DataStringStream := TStringStream.Create('''');
try
DataStringStream.CopyFrom(AData,