Imports System
Imports System.Net
Imports System.Net.Sockets
Imports System.Threading
Imports System.Text


Public Class Form1

	Private client As AsynchronousClient = Nothing
	Private address As IPAddress = Nothing

	Private Sub Log(message As String)
		recievedDataList.Text += message
		recievedDataList.SelectionStart = recievedDataList.TextLength
		recievedDataList.ScrollToCaret()
	End Sub

	Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
		disconnect.Enabled = False
		sendData.Enabled = False
		data.Enabled = False
	End Sub

	Private Sub Button1_Click(sender As Object, e As EventArgs) Handles connect.Click
		If (ipAddress.Text IsNot "") Then
			If (System.Net.IPAddress.TryParse(ipAddress.Text, address)) Then
				If (IsNothing(client)) Then
					client = New AsynchronousClient(SocketType.Stream, ProtocolType.Tcp)
				End If
				client.Connect(address, port.Value)
				AddHandler client.ReceivedData, AddressOf onRecievedData
				AddHandler client.Loged, AddressOf onLogEvent
				AddHandler client.Connected, AddressOf onConnect
				AddHandler client.Disconnected, AddressOf onDisconnect

			End If
		End If
	End Sub

	Private Sub onDisconnect()
		Me.BeginInvoke(
		Sub()
			disconnect.Enabled = False
			connect.Enabled = True
			sendData.Enabled = False
			data.Enabled = False
			client.Close()
			client = Nothing
		End Sub
		)
	End Sub

	Private Function onConnect() As Object
		Me.BeginInvoke(
		Sub()
			disconnect.Enabled = True
			connect.Enabled = False
			sendData.Enabled = True
			data.Enabled = True
		End Sub
		)
	End Function

	Private Sub onLogEvent(message As String)
		Me.BeginInvoke(Sub() Log(message))
	End Sub

	Private Sub onRecievedData(data As String)
		Me.BeginInvoke(Sub() Log(data))
	End Sub

	Private Sub SendData_Click(sender As Object, e As EventArgs) Handles sendData.Click
		Dim dataInt As Int32 = data.Value
		client.Send(dataInt.ToString())
	End Sub

	Private Sub disconnect_Click(sender As Object, e As EventArgs) Handles disconnect.Click
		client.Disconnect()
	End Sub

	Private Sub AboutUsToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles AboutUsToolStripMenuItem.Click
		Process.Start("https://github.com/sampad1370/SocketInVB")
	End Sub
End Class

' State object for receiving data from remote device.  
Public Class StateObject

	' Client socket.  
	Public workSocket As Socket = Nothing

	' Size of receive buffer.  
	Public Const BufferSize As Integer = 256

	' Receive buffer.  
	Public buffer() As Byte = New Byte((BufferSize) - 1) {}

	' Received data string.  
	Public sb As StringBuilder = New StringBuilder
End Class

Public Class AsynchronousClient

	' ManualResetEvent instances signal completion.  
	Public connectDone As ManualResetEvent = New ManualResetEvent(False)

	Public disconnectDone As ManualResetEvent = New ManualResetEvent(False)

	Public sendDone As ManualResetEvent = New ManualResetEvent(False)

	Public receiveDone As ManualResetEvent = New ManualResetEvent(False)


	' The response from the remote device.  
	Public response As String = String.Empty

	Private client As Socket = Nothing

	Public Event ReceivedData(data As String)
	Public Event Loged(message As String)
	Public Event Connected()
	Public Event Disconnected()

	Public Sub New(socketType As SocketType, protocolType As ProtocolType)
		client = New Socket(socketType, protocolType)

		client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, True)


	End Sub

	Private Sub ConnectCallback(ByVal ar As IAsyncResult)
		Try
			' Retrieve the socket from the state object.  
			Dim client As Socket = CType(ar.AsyncState, Socket)
			' Complete the connection.  
			client.EndConnect(ar)
			RaiseEvent Loged("Socket connected to " + client.RemoteEndPoint.ToString() + vbCrLf)
			' Signal that the connection has been made.  
			connectDone.Set()
			RaiseEvent Connected()
			Receive(client)
		Catch e As Exception
			RaiseEvent Loged(e.ToString)
		End Try

	End Sub

	Private Sub DisconnectCallback(ar As IAsyncResult)
		Try
			' Retrieve the socket from the state object.  
			Dim client As Socket = CType(ar.AsyncState, Socket)
			client.EndDisconnect(ar)
			disconnectDone.[Set]()
			RaiseEvent Loged("Socket disconnected to " + client.RemoteEndPoint.ToString() + vbCrLf)
			RaiseEvent Disconnected()
			' Signal that the connection has been made.
		Catch e As Exception
			RaiseEvent Loged(e.ToString)
		End Try
	End Sub

	Public Sub Connect(ipAddress As IPAddress, port As Int32)
		client.BeginConnect(ipAddress, port, New AsyncCallback(AddressOf ConnectCallback), client)
	End Sub

	Public Sub Disconnect()
		client.Shutdown(SocketShutdown.Both)
		client.BeginDisconnect(True, New AsyncCallback(AddressOf DisconnectCallback), client)
	End Sub

	Private Sub Receive(ByVal client As Socket)
		Try
			' Create the state object.  
			Dim state As StateObject = New StateObject
			state.workSocket = client
			' Begin receiving the data from the remote device.  
			client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0, New AsyncCallback(AddressOf ReceiveCallback), state)
		Catch e As Exception
			RaiseEvent Loged(e.ToString)
		End Try

	End Sub

	Private Sub ReceiveCallback(ByVal ar As IAsyncResult)
		Try
			' Retrieve the state object and the client socket   
			' from the asynchronous state object.  
			Dim state As StateObject = CType(ar.AsyncState, StateObject)
			Dim client As Socket = state.workSocket
			' Read data from the remote device.  
			Dim bytesRead As Integer = client.EndReceive(ar)
			If (bytesRead > 0) Then
				' There might be more data, so store the data received so far.
				Dim str As String = Encoding.ASCII.GetString(state.buffer, 0, bytesRead)
				state.sb.Append(str)
				' Get the rest of the data.  

				If (str.Length > 1) Then
					RaiseEvent ReceivedData(str)
				End If

				' Signal that all bytes have been received.  
				receiveDone.Set()
				client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0, New AsyncCallback(AddressOf ReceiveCallback), state)
			Else
				' All the data has arrived; put it in response.  
				' Must change strategye to best detect packet 
			End If

		Catch e As Exception
			RaiseEvent Loged(e.ToString)
		End Try

	End Sub

	Private Sub Send(ByVal client As Socket, ByVal data As String)
		' Convert the string data to byte data using ASCII encoding.  
		Dim byteData() As Byte = Encoding.ASCII.GetBytes(data)
		' Begin sending the data to the remote device.  
		client.BeginSend(byteData, 0, byteData.Length, 0, New AsyncCallback(AddressOf SendCallback), client)
	End Sub

	Private Sub SendCallback(ByVal ar As IAsyncResult)
		Try
			' Retrieve the socket from the state object.  
			Dim client As Socket = CType(ar.AsyncState, Socket)
			' Complete sending the data to the remote device.  
			Dim bytesSent As Integer = client.EndSend(ar)
			RaiseEvent Loged("Sent " + bytesSent.ToString() + " bytes to server.")
			' Signal that all bytes have been sent.  
			sendDone.Set()
		Catch e As Exception
			Console.WriteLine(e.ToString)
		End Try

	End Sub

	Public Sub Send(ByVal data As String)
		' Convert the string data to byte data using ASCII encoding.  
		Dim byteData() As Byte = Encoding.ASCII.GetBytes(data & vbLf)
		' Begin sending the data to the remote device.  
		'client.BeginSend(byteData, 0, byteData.Length, 0, New AsyncCallback(AddressOf SendCallback), client)
		client.Send(byteData)
	End Sub

	Public Sub Close()
		client.Close()
	End Sub
End Class