2、弄通TIdTCPClient

第一：TIdTCPClient是何物？从下图可以看出，它是Delphi自带的Indy组件之一：

 

 

 

第二，明白了TIdTCPClient是何物，接下来应当明白它的用法：

 

首先编写客户端程序， 启动Delphi7新建一个程序，拖几个控件：Button/TIdTCPClient/listbox，在Button单击事件里写代码，功能是：

按下此按钮时，连接远方的服务器（显然，远方的服务器要事先处于Active状态），连接成功后，读取远方的信息，

当远方服务程序收到一个连接时，便会执行：procedure IdTCPServer1Execute(AThread: TIdPeerThread);，在此过程里

向客户发送信息。

 

客户代码如下：(里面的注释有误,//将服务端收到的数据添加到列表中

procedure TFClient.Button1Click(Sender: TObject); begin with TCPClient do begin //建立与服务器的连接 Connect; try //将客户端收到的数据添加到列表中 ListBox1.Items.Add(ReadLn); finally Disconnect; end; end; end; end.

 

服务端代码如下：

unit U_Server; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, IdBaseComponent, IdComponent, IdTCPServer; type TFServer = class(TForm) IdTCPServer1: TIdTCPServer; procedure FormCreate(Sender: TObject); procedure IdTCPServer1Execute(AThread: TIdPeerThread); private { Private declarations } public { Public declarations } end; var FServer: TFServer; implementation {$R *.dfm} procedure TFServer.FormCreate(Sender: TObject); begin IdTCPServer1.Active := True; end; procedure TFServer.IdTCPServer1Execute(AThread: TIdPeerThread); begin with AThread.Connection do begin //向与服务器连接的客户发送一条简单的消息 WriteLn('欢迎访问TCP服务器！'); //断开连接 Disconnect; end; end; end.

 

结论:

上面的例子，完成了从服务端获取一条命令。本例子就算作入门Delphi 7 的第一个程序吧。

代码下载:

unit UClient; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, ExtCtrls, IdBaseComponent, IdComponent, IdTCPConnection, IdTCPClient; type TFClient = class(TForm) ListBox1: TListBox; TCPClient: TIdTCPClient; Button1: TButton; procedure Button1Click(Sender: TObject); private { Private declarations } public { Public declarations } end; var FClient: TFClient; implementation {$R *.dfm} procedure TFClient.Button1Click(Sender: TObject); begin with TCPClient do begin //建立与服务器的连接 Connect; try //将客户端收到的数据添加到列表中 ListBox1.Items.Add(ReadLn); finally Disconnect; end; end; end; end. unit U_Server; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, IdBaseComponent, IdComponent, IdTCPServer; type TFServer = class(TForm) IdTCPServer1: TIdTCPServer; procedure FormCreate(Sender: TObject); procedure IdTCPServer1Execute(AThread: TIdPeerThread); private { Private declarations } public { Public declarations } end; var FServer: TFServer; implementation {$R *.dfm} procedure TFServer.FormCreate(Sender: TObject); begin IdTCPServer1.Active := True; end; procedure TFServer.IdTCPServer1Execute(AThread: TIdPeerThread); begin with AThread.Connection do begin //向与服务器连接的客户发送一条简单的消息 WriteLn('欢迎访问TCP服务器！'); //断开连接 Disconnect; end; end; end.