Creating a Port Scanner in C#

Creating a Port Scanner in C#/List all occupied ports in a System



     IPGlobalProperties gp=System.Net.NetworkInformation.IPGlobalProperties.GetIPGlobalProperties();
            Console.WriteLine("Computer Name={0}",gp.HostName);

            Console.WriteLine("TCP Active Listeners");
            foreach (IPEndPoint ipe in gp.GetActiveTcpListeners())
            {
                Console.WriteLine(ipe.Address+"\t\t"+ipe.AddressFamily+"\t\t"+ipe.Port);
            }
OUTPUT

List Active Tcp Active Connections  using C#

            IPGlobalProperties gp=System.Net.NetworkInformation.IPGlobalProperties.GetIPGlobalProperties();

            Console.WriteLine("Computer Name={0}",gp.HostName);

            Console.WriteLine("TCP Active TCP Connections");

            foreach(TcpConnectionInformation tci in gp.GetActiveTcpConnections())

            {

                Console.WriteLine(tci.LocalEndPoint.Address + "\t\t" + tci.LocalEndPoint.AddressFamily + "\t\t" + tci.LocalEndPoint.Port);

            }

OUTPUT

Enumerate Files in a Directory using LINQ

List All files in a Directory using LINQ


            expr=System.IO.Directory.EnumerateFiles("C:\\");
            foreach (String file in expr)
            {
                Console.WriteLine(file);
            }

It displays complete path+filename.

Enumerate Directories using C#

list all directories  in C drive using C#

      var expr=System.IO.Directory.EnumerateDirectories(@"c:\");

            foreach (String file in expr)

            {

                Console.WriteLine(file);

            }

Dynamic Sized Arrays in C#

In Static Arrays Array size should be defined at compile time.  In some cases programmer may not know exact size of the array.  At that time, Programer can create dynamic arrays using following code.


       Array dynamicSizeArray= Array.CreateInstance(typeof(string), 2);
       dynamicSizeArray.SetValue("Hello",0);
       dynamicSizeArray.SetValue("World", 1);

       Console.Write(dynamicSizeArray.GetLength(0));
        Console .Write(dynamicSizeArray.GetUpperBound(0));

The above code Creates  an Single Dimensional Array of size 2  of type string.

0th location holds Hello

1st location holds World

GetLength method returns 2

GetUpperBound return 1.

Note: Programmer can create multi-dimenstional arrays using Array.CreateInstance method