应用TIdECHOServer和TIdEcho组件

(1) unit U_Echo_Client;interfaceuses  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,  Dialogs, IdBaseComponent, IdComponent, IdTCPConnection, IdTCPClient,  IdEcho, StdCtrls;type  TEcho_Client = class(TForm)    Label1: TLabel;    Label2: TLabel;    Label3: TLabel;    Label4: TLabel;    BConnect: TButton;    BSend: TButton;    BDisCon: TButton;    EAddress: TEdit;    EText: TEdit;    LTime: TLabel;    LReceive: TLabel;    IdEcho1: TIdEcho;    procedure BConnectClick(Sender: TObject);    procedure BSendClick(Sender: TObject);    procedure BDisConClick(Sender: TObject);    procedure FormCreate(Sender: TObject);    procedure FormCloseQuery(Sender: TObject; var CanClose: Boolean);    procedure EAddressChange(Sender: TObject);  private    { Private declarations }  public    { Public declarations }  end;var  Echo_Client: TEcho_Client;implementation{$R *.dfm}procedure TEcho_Client.FormCreate(Sender: TObject);begin    BConnect.Enabled := True;  //激活“连接”按钮    EText.Enabled := False;   //禁用发送文本框    EText.color := clSilver;    BSend.Enabled :=False;  //禁用“发送”按钮    BDisCon.Enabled := False; //禁用“断开连接”按钮end;procedure TEcho_Client.FormCloseQuery(Sender: TObject;  var CanClose: Boolean);begin   IdEcho1.Disconnect;end;procedure TEcho_Client.EAddressChange(Sender: TObject);begin  // 设置要连接的服务器的地址 IdEcho1.Host := EAddress.Text;end;procedure TEcho_Client.BConnectClick(Sender: TObject);begin  try    //建立与Echo服务器的连接    IdEcho1.Connect;    EText.Enabled := True;  //激活发送文本框    EText.color := clWhite;    BSend.Enabled := True;//激活“发送”按钮    BDisCon.Enabled := True;//激活“断开连接”按钮    BConnect.Enabled :=False;//禁用“连接”按钮  except    //断开与Echo服务器的连接    IdEcho1.Disconnect;    ShowMessage('连接失败，请检查服务器是否运行！');  end; //try..exceptend;procedure TEcho_Client.BSendClick(Sender: TObject);begin  //对发送文本框的内容不为‘’的情况进行处理  if EText.Text<>'' then    begin      //发送并接收回声数据      lTime.Caption := IdEcho1.Echo ( EText.Text );      //显示发送和接收回声数据所需的时间      LReceive.Caption := IntToStr ( IdEcho1.EchoTime );    end  //对发送文本框的内容为‘’的情况进行处理  else    begin      lTime.Caption :='';      LReceive.Caption :='';    end;      end;procedure TEcho_Client.BDisConClick(Sender: TObject);begin  //断开与Echo服务器的连接  IdEcho1.Disconnect;  BConnect.Enabled := True;  //激活“连接”按钮  EText.Enabled := False;   //禁用发送文本框  EText.color := clSilver;  BSend.Enabled :=False;  //禁用“发送”按钮  BDisCon.Enabled := False; //禁用“断开连接”按钮end;end.(2) unit U_Echo_Server;interfaceuses  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,  Dialogs, StdCtrls, IdBaseComponent, IdComponent, IdTCPServer,  IdEchoServer;type  TF_Echo_Server = class(TForm)    Label1: TLabel;    Label2: TLabel;    Button1: TButton;    IdECHOServer1: TIdECHOServer;    procedure Button1Click(Sender: TObject);    procedure FormActivate(Sender: TObject);    procedure IdECHOServer1Disconnect(AThread: TIdPeerThread);    procedure IdECHOServer1Connect(AThread: TIdPeerThread);  private    { Private declarations }  public    { Public declarations }  end;var  F_Echo_Server: TF_Echo_Server;implementation{$R *.dfm}procedure TF_Echo_Server.FormActivate(Sender: TObject);begin try //激活TIdECHOServer组件  IdECHOServer1.Active := True; except  ShowMessage('拒绝连接！由于安全的原因无法绑定到预定的端口！');  Application.Terminate; end;end;procedure TF_Echo_Server.IdECHOServer1Disconnect(AThread: TIdPeerThread);begin  //更新窗体上显示的服务器状态  Label2.caption := '[ 空闲－等待新用户 ]';end;procedure TF_Echo_Server.IdECHOServer1Connect(AThread: TIdPeerThread);begin //更新窗体上显示的服务器状态 Label2.caption := '[ 服务于客户 ]';end;procedure TF_Echo_Server.Button1Click(Sender: TObject);begin  if IdECHOServer1.active then    IdECHOServer1.active := false;  Application.terminate;end;end.