-> PortScanner added

Networking/PortScanner/TCPPortScanner.cs

@@ -0,0 +1,56 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net.Sockets;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace PortScanner
+{
+    class TCPPortScanner : PortScannerBase
+    {
+        // The TCP client for port scanning 
+        private TcpClient tcpClient;
+
+        // Constructor - uses base class constructor
+        public TCPPortScanner() : base()
+        {
+        }
+
+        // Implementing the base's abstract method CheckOpenAsync(), cancellation token ct passed from MainWindow, triggered in the cancel button click event
+        public override async Task<bool> CheckOpenAsync(CancellationToken ct)
+        {
+            using (tcpClient = new TcpClient())
+            {
+                // connection is the Task returned by ConnectAsync
+                var connection = tcpClient.ConnectAsync(Hostname, Port);
+
+                bool returnValue;
+                
+                // In case the ct is triggered, this will act as if delay expired right when the click occurrs
+                if (await Task.WhenAny(connection, Task.Delay(Timeout, ct)) == connection)
+                {
+                    // If connection was refused, return false
+                    // The exception within the task is a SocketException if the connection failed
+                    if (connection.Exception != null)
+                    {
+                        returnValue = false;
+                    }
+                    else
+                    {
+                        returnValue = true;
+                    }
+                }
+                else
+                {
+                    // Timeout occurred, this means that there is no connection and port is closed
+                    returnValue = false;
+                }
+
+                tcpClient.Close();
+                return returnValue;
+            }
+        }
+    }
+}