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This article mainly shows you "how to use VB to write a remote control program", the content is easy to understand, clear, hope to help you solve doubts, the following let the editor lead you to study and learn "how to use VB to write a remote control program" this article.

I. the controls used

The Winsock control will be used in the program. The Winsock control is an ActiveX control that connects to and exchanges data with a remote computer using the TCP or UDP protocols. Like timer controls, Winsock controls are not visible at run time. The working principle of Winsock is: the client sends a connection request to the server, and the server keeps listening to the client's request. When the two protocols communicate, a connection is established between the client and the server, and then the client and the server can realize two-way data transmission. In practical programming, a server-side application and a client-side application must be established respectively, and the two applications have their own Winsock controls. First set the protocol used by the Winsock control, here we use the TCP protocol. Now, let's start to use VB to build two programs, one is the client program myclient, and the other is the server-side program myserver.

II. VB.NET programming client

First of all, let's build the client program myclient. Set up a form in the myclient program and load the Winsock control called tcpclient, which means that the TCP protocol is used. Add two text boxes (text1 and text2) to enter the IP address and port number of the server, and then set up a button (cd1) to establish the connection. After pressing, the connection can be initialized as follows:

Privatesubcd1_click () tcpclient.romotehost=text1.text tcpclient.romoteport=val (text2.text) 'port number, which defaults to 1001 tcpclient.connect' to call the connect method to connect cd1.enabled=false endsub to the computer with the specified IP address

After the connection, there is the question of how to deal with the data received. After establishing a connection between the client and the server, if any side receives new data, it will trigger the dataarrival event of the winsock control on that end. In response to this event, you can use the getdata method to get the sent data. For example, you can write code in the dataarrival event of tcpclient as follows:

Privatesubtcpclient_dataarrival (byvalbytestotalaslong) dimxasstring tcpclient.getdatax' uses getdata to get the data sent. Endsub

The following ellipsis section indicates the specific processing of the received data, which the reader can write according to the actual situation.

3. Server side of VB.NET programming

First create a form and load the Winsock control with the name tcpserver. In addition, a text box text1 is added to the form to display the IP address of the client and the data information sent by the client.

When the client program is running, after the client program presses the connection button, the client requests a connection from the server-side program, and the server-side connectionrequest event is triggered, so the server-side program can use the connectionrequest event to solve the connection problem. The code is as follows:

'initialize the tcpserver control in the load event of the form privatesubform_load () tcpserver.localport=1001 tcpserver.listen' put the server in the listening detection state endsub 'the server receives the connection request from the client, first check whether the current state is in the connection closed state Privatesubtcpclient_connectionrequest (ByvalrequestIDaslong) Iftcpserver.statesckclosedthen' check whether the state property of the control is to close Tcpserver.close' Tcpserver.acceptrequestID' Endif Endsub

Now let's add the following code to the dataarrival event of the server-side program tcpserver so that the server-side program can receive client-side instructions and run the corresponding program.

4. Remote control of VB.NET program testing

Now you can run these two programs on two machines connected to the Internet using the TCP/IP protocol. On the client side, you press the connect button and type "c:mmand.com". You can see that a DOS window opens immediately on the server side. Imagine what happens if it runs some destructive commands. This is the most basic remote control program. Of course, the real hacker program is much more complex, but the basic principles are the same.

The above is all the contents of the article "how to write a remote control program using VB". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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