update

MySolution/ConsoleApp/TelnetSamples/AsyncSocketTelnetClient.cs

@@ -12,17 +12,18 @@ namespace ConsoleApp.TelnetSamples
 {
 	internal class AsyncSocketTelnetClient : IAsyncTelnetClient
 	{
-		private readonly CancellationTokenSource CTS = new CancellationTokenSource();
+		private CancellationTokenSource _cts;
 
 		public event EventHandler<string> MessageCallback;
+		public event EventHandler<Exception> ErrorCallback;
 
-		private Socket _socket;
+        private Socket _socket;
 
 		public async void Connect(string ip, int port = 23)
 		{
 			try
 			{
-				Close();
+				//Close();
 
 				_socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
 				_socket.ReceiveTimeout = 1000;
@@ -31,28 +32,37 @@ namespace ConsoleApp.TelnetSamples
 				IPEndPoint iPEndPoint = new IPEndPoint(ipAddress, port);
 				await _socket.ConnectAsync(iPEndPoint);
 
-				Task.Run(ReadAsync);
+				_cts = new CancellationTokenSource();
+				Task.Run(ReadAsync, _cts.Token);
 			}
-			catch (Exception)
+			catch (Exception ex)
 			{
-				throw;
-			}
+                if (this.ErrorCallback != null)
+                    this.ErrorCallback(this, ex);
+            }
 		}
 
 		private async void ReadAsync()
 		{
 			try
 			{
-
 				StringBuilder sb = new StringBuilder();
 				byte[] readBuffer = new byte[1024];
 				while (true)
 				{
-					int bytesRead = await _socket.ReceiveAsync(readBuffer);
-					if (bytesRead < 1)
+					if (_cts != null && _cts.IsCancellationRequested)
 						break;
 
-					string data = Encoding.ASCII.GetString(readBuffer, 0, bytesRead);
+					int bytesRead = _cts != null && _cts.IsCancellationRequested ? 0 : await _socket.ReceiveAsync(readBuffer);
+					if (bytesRead < 1)
+					{
+						if (sb.Length > 0 && this.MessageCallback != null)
+							this.MessageCallback(this, sb.ToString());
+
+                        break;
+                    }
+
+                    string data = Encoding.ASCII.GetString(readBuffer, 0, bytesRead);
 					sb.Append(data);
 
 					if (!data.EndsWith("\r\n>"))
@@ -69,25 +79,31 @@ namespace ConsoleApp.TelnetSamples
 					sb.Clear();
 				}
 			}
-			catch (Exception)
-			{
-				throw;
-			}
-		}
+            catch (Exception ex)
+            {
+                if (this.ErrorCallback != null)
+                    this.ErrorCallback(this, ex);
+            }
+        }
 
 		public async void SendCommand(string command)
 		{
 			try
 			{
+				command = command.Replace(" ", "");
+				if (string.IsNullOrEmpty(command))
+					return;
+
 				command += "\r\n";
 				byte[] sendBytes = Encoding.ASCII.GetBytes(command);
 				await _socket.SendAsync(sendBytes);
 			}
-			catch (Exception)
-			{
-				throw;
-			}
-		}
+            catch (Exception ex)
+            {
+                if (this.ErrorCallback != null)
+                    this.ErrorCallback(this, ex);
+            }
+        }
 
 		public void Close()
 		{
@@ -96,14 +112,17 @@ namespace ConsoleApp.TelnetSamples
 				if (_socket == null)
 					return;
 
+				_cts.Cancel();
+
 				_socket.Shutdown(SocketShutdown.Both);
 				_socket.Close();
 				_socket.Dispose();
 			}
-			catch (Exception)
-			{
-				throw;
-			}
-		}
+            catch (Exception ex)
+            {
+                if (this.ErrorCallback != null)
+                    this.ErrorCallback(this, ex);
+            }
+        }
 	}
 }