(RPM) implements a simple Ping function in C # to test whether the network is connected

This article was reprinted from: http://blog.csdn.net/xiamin/archive/2009/02/14/3889696.aspx

Implement a simple Ping function in C # to test whether the network is connected

1. Get host name based on IP address

 /// <summary>        ///get host name based on IP address/// </summary>        /// <param name= "IP" >IP address of the host</param>        /// <returns>Host name</returns>         Public stringGethostnamebyip (stringIP) {IP=IP.            Trim (); if(IP = =string. Empty)return string.            Empty; Try            {                //whether the Ping is a pass                if( This. Ping (IP)) {System.Net.IPHostEntry host=System.Net.Dns.GetHostEntry (IP); returnhost.                HostName; }                Else                    return string.            Empty; }            Catch(Exception) {return string.            Empty; }        }

Note: If your computer can access the Internet you can even query to: the IP Address "64.233.189.104" is a Google named "hk-in-f104.google.com" the IP address of the host.

About this in the code. After the Ping (IP) method.

Now that you've said how to "get the hostname based on the IP address," say how to "get the host's IP address based on the hostname".

2. Obtain the host's IP address according to the host name

 /// <summary>        ///Obtain the host's IP address based on the hostname (domain name)/// </summary>        /// <param name= "HostName" >host name or domain name</param>        /// <example>Getipbydomain ("www.google.com");</example>        /// <returns>IP address of the host</returns>         Public stringGetipbyhostname (stringhostName) {HostName=Hostname.trim (); if(HostName = =string. Empty)return string.            Empty; Try{System.Net.IPHostEntry host=System.Net.Dns.GetHostEntry (hostName); returnHost. Addresslist.getvalue (0).            ToString (); }            Catch(Exception) {return string.            Empty; }        }

Note: If your computer can surf the Internet you can even query to: "www.google.com" IP address is "64.233.189.104".

Finally, say that C # implements a simple Ping function to test whether the network is connected.

3. C # implements a simple Ping function to test whether the network is connected

/// <summary>        ///whether the specified host can be Ping/// </summary>        /// <param name= "IP" >IP address or host name or domain name</param>        /// <returns>true Pass, false not pass</returns>         Public BOOLPing (stringIP) {System.Net.NetworkInformation.Ping P=NewSystem.Net.NetworkInformation.Ping (); System.Net.NetworkInformation.PingOptions Options=NewSystem.Net.NetworkInformation.PingOptions (); Options. Dontfragment=true; stringdata ="Test data!"; byte[] buffer =Encoding.ASCII.GetBytes (data); intTimeout = +;//timeout time, unit: millisecondsSystem.Net.NetworkInformation.PingReply reply =p.send (IP, timeout, buffer, options); if(reply. Status = =System.Net.NetworkInformation.IPStatus.Success)return true; Else                return false; }

Private voidButton1_Click (Objectsender, EventArgs e)//Get IP{textbox2.text=Getipbyhostname (TextBox1.Text); }  Private voidButton2_Click (Objectsender, EventArgs e)//Get host name{textbox1.text=Gethostnamebyip (TextBox2.Text); }   Private voidButton3_Click (Objectsender, EventArgs e)//get the native IP        {            stringHostName =System.Net.Dns.GetHostName (); Iphostentry Ipentry=System.Net.Dns.GetHostEntry (hostName); //Dns.gethostbyname (myName); obsoleteipaddress[] Addr =ipentry.addresslist; TextBox2.Text= addr[0].        ToString (); }        /// <summary>        ///LAN Search Events/// </summary>        Private voidLansearch () {stringlocalhost =(Dns.gethostentry (Dns.gethostname ())). addresslist[0]. ToString ();//Local Host IP address            stringstr = localhost. Substring (0, localhost. LastIndexOf ("."));  for(inti =0; I <255; i++)//set up 255 threads to scan an IP            {                stringIP = str +"."+i.tostring ();  This. Text =IP; if(Ping (IP)) {LISTBOX1.ITEMS.ADD (IP);                 Application.doevents (); } progressbarsearch.value= Progressbarsearch.value +1; }        }        Private voidButton4_Click (Objectsender, EventArgs e)//Online Hosting{lansearch (); }

(RPM) implements a simple Ping function in C # to test whether the network is connected