Create Chat Group Using VB.Net

Hello friends, in this post I will discuss about how to create a simple chat group app that is connected on the same network, using Visual Studio IDE. Such an application is certainly very useful to exchange information, for example if two employees who want to communicate but the first employee is on the 1st floor while the other employees are on the 2nd floor. That's one example of the benefits of this kind of application and of course there are still benefits other.

Now open and create a new project in Visual Studio, then design a form as server more or less as shown below

NOTES :

Componen Form Server :

• 4 Label
• 2 TextBox
• 2 RichTextBox
• 1 Button
• 1 PictureBox

Next, create a new project again and design the form as a client more or less like in the picture below

NOTES :

Componen Form Client :

• 2 Label
• 3 TextBox
• 2 Button
• 1 RichTextBox

Now, we go back to the project form server, then create a module and name it CPcontrolClass and enter the following code

Imports System.Net
Imports System.Net.Sockets
Imports System.Threading
Imports System.IO

Public Class CPcontrolClass
    Public Event MessageReceived(ByVal sender As CPcontrolClass, ByVal Data As String)        
    Public serverIP As IPAddress = IPAddress.Parse("127.0.0.1")
    Public serverPORT As Integer = 8080
    Public server As TcpListener
    Private comThread As Thread
    Public isListening As Boolean = True
    Private client As TcpClient
    Private clientData As StreamReader

    Public Sub New()
        server = New TcpListener(serverIP, serverPORT)
        server.Start()
        comThread = New Thread(New ThreadStart(AddressOf Listening))
        comThread.Start()
    End Sub
    Public Sub ipnya()
        Dim addrs As IPAddress
        Dim x As Byte = 0
        Do
            addrs = Dns.GetHostEntry(Dns.GetHostName).AddressList(x)
            x += 1
        Loop Until (addrs.AddressFamily = AddressFamily.InterNetwork)
    End Sub
    Private Sub Listening()
        Do Until isListening = False
            If server.Pending = True Then
                client = server.AcceptTcpClient
                clientData = New StreamReader(client.GetStream)
            End If

            Try
                RaiseEvent MessageReceived(Me, clientData.ReadLine)
                My.Computer.Audio.PlaySystemSound(Media.SystemSounds.Beep)
            Catch ex As Exception
            End Try
            Thread.Sleep(100)
        Loop
    End Sub
End Class

NOTES :

127.0.0.1 is the local IP Address, if you want to use with a different device, please replace it with your device's ip address.

After that, import some of the required libraries on the server form

Imports System.Net
Imports System.Net.Sockets
Imports System.Runtime.InteropServices
Imports System.Threading
Imports System.IO

Public Class Form1

End Class

Then, declare some global variables

Public Class Form1
    Private server As CPcontrolClass
    Dim log As String
    Dim ipserver As IPAddress
    Private TCPListener As TcpListener
    Private clientCollection As New Hashtable()
    Private usernameCollection As New Hashtable()
    Private Shared connectID As Long = 0
    Private serverThread As Thread
    Public Delegate Sub updateListboxDelegate(ByVal str As String)   
    Dim clientThread As System.Threading.Thread
    Dim client As New TcpClient
    Dim reader As BinaryReader
    Dim writer As BinaryWriter
    Dim message As String
    Dim username As String
    Delegate Sub updateMessageDelegate(ByVal message As String)      
    Delegate Sub updateUserDelegate(ByVal message As String)
End Class

Then, create some of the following functions

Public Structure ClientData
        Public structSocket As TcpClient
        Public structThread As Thread
        Public structReader As BinaryReader
        Public structWriter As BinaryWriter
    End Structure

    Sub updateMessageWork(ByVal message As String)
        RichTextBox1.AppendText(message + vbNewLine)
    End Sub

    Sub updateMessage(ByVal message As String)
        If RichTextBox1.InvokeRequired Then
            Invoke(New updateMessageDelegate(AddressOf updateMessageWork), message)
        Else
            RichTextBox1.AppendText(message + vbNewLine)
        End If
    End Sub

    Sub updateUserWork(ByVal message As String)
        Dim userlist() As String = Split(message, Chr(13))
        Dim i As Integer
        lbUser.Items.Clear()
        For i = 0 To userlist.Length - 1
            lbUser.Items.Add(userlist(i))
        Next
    End Sub

    Sub updateUser(ByVal message As String)
        If lbUser.InvokeRequired Then
            Invoke(New updateUserDelegate(AddressOf updateUserWork), message)
        End If
    End Sub

    Public Sub readSocket()
        Dim realId As Long = connectID
        Dim CData As New ClientData
        CData = CType(clientCollection(realId), ClientData)
        Dim message As String

        Dim found As Boolean = False

        While True
            If CData.structSocket.Connected Then
                Try
                    message = CData.structReader.ReadString()
                    If message.Substring(0, 3) = "MES" Then
                        For Each Client As ClientData In clientCollection.Values
                            If Client.structSocket.Connected Then
                                Client.structWriter.Write(message)
                            End If
                        Next
                    ElseIf message.Substring(0, 3) = "USR" Then
                        For Each user As String In usernameCollection.Values()
                            If user = message.Substring(4) Then
                                found = True
                            End If
                        Next
                        If found = True Then
                            message = "err"
                            For Each Client As ClientData In clientCollection.Values()
                                If Client.structSocket.Connected Then
                                    Client.structWriter.Write(message)
                                    Exit For
                                End If
                            Next
                            Try
                                Dim client As ClientData = CType(clientCollection(realId), ClientData)   
                                client.structThread.Abort()
                            Catch e As Exception
                                SyncLock Me
                                    clientCollection.Remove(realId)
                                    usernameCollection.Remove(realId)
                                End SyncLock
                            End Try
                        Else
                            usernameCollection.Add(realId, message.Substring(4))
                            Dim userlist As String = ""
                            For Each user As String In usernameCollection.Values()
                                userlist = userlist & user & Chr(13)
                            Next
                            For Each Client As ClientData In clientCollection.Values()
                                If Client.structSocket.Connected Then
                                    Client.structWriter.Write("USR " & userlist)
                                End If
                            Next
                        End If
                    ElseIf message.Substring(0, 3) = "DIS" Then
                        usernameCollection.Remove(realId)
                        Dim userlist As String = ""
                        For Each user As String In usernameCollection.Values()
                            userlist = userlist & user & Chr(13)
                        Next

                        For Each Client As ClientData In clientCollection.Values()
                            If Client.structSocket.Connected Then
                                Client.structWriter.Write("USR " & userlist)
                            End If
                        Next
                    End If
                Catch e As Exception
                    Exit While
                End Try
            End If
        End While
        CloseTheThread(realId)
    End Sub
    Private Sub CloseTheThread(ByVal realId As Long)
        Try
            Dim client As ClientData = CType(clientCollection(realId), ClientData)
            client.structThread.Abort()
        Catch e As Exception
            SyncLock Me
                clientCollection.Remove(realId)
                usernameCollection.Remove(realId)
            End SyncLock
        End Try
    End Sub

    Private Sub OnlineReceived(ByVal sender As CPcontrolClass, ByVal Data As String)
    End Sub
    Public Sub readSocketClient()
        While True
            Try
                message = reader.ReadString()
                If message.Substring(0, 3) = "MES" Then
                    updateMessage(message.Substring(4))
                ElseIf message.Substring(0, 3) = "USR" Then
                    updateUser(message.Substring(4))
                ElseIf message.Substring(0, 3) = "DIS" Then
                    updateUser(message.Substring(4))
                End If
                If message = "err" Then
                    Exit Sub
                End If
            Catch e As Exception
                Exit While
            End Try
        End While
    End Sub

    Public Sub writeSocket(ByVal message As String)
        If client.Connected Then
            writer.Write(message)
        End If
    End Sub
    Sub startConnect()
        Try
            client = New TcpClient()
            client.Connect(ipserver, 8888)
            reader = New BinaryReader(client.GetStream())
            writer = New BinaryWriter(client.GetStream())

            writer.Write("USR  " + TextBox1.Text)
            username = TextBox1.Text
            clientThread = New System.Threading.Thread(AddressOf readSocketClient)
            clientThread.Start()
            server = New CPcontrolClass
            AddHandler server.MessageReceived, AddressOf OnlineReceived

            RichTextBox1.Visible = True
            lbUser.Visible = True



        Catch ex As Exception
            Exit Sub
        End Try
    End Sub
    Public Sub New()
        InitializeComponent()
    End Sub
    Public Sub waitingForClient()
        Dim CData As New ClientData
        While True
            CData.structSocket = TCPListener.AcceptTcpClient
            Interlocked.Increment(connectID)
            CData.structThread = New Thread(AddressOf readSocket)
            CData.structReader = New BinaryReader(CData.structSocket.GetStream())
            CData.structWriter = New BinaryWriter(CData.structSocket.GetStream())
            SyncLock Me
                clientCollection.Add(connectID, CData)
            End SyncLock
            CData.structThread.Start()
        End While
    End Sub

Then, double-click Button1 and enter the following code

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click   
        If TextBox1.Text = "" Or TextBox3.Text = "" Then
            MsgBox("please complete the field", MsgBoxStyle.Exclamation)
        Else
            Dim addr As IPAddress = IPAddress.Parse(TextBox3.Text)
            ipserver = addr
            TCPListener = New TcpListener(addr, 8888)
            TCPListener.Start()
            serverThread = New Thread(AddressOf waitingForClient)
            serverThread.Start()
            startConnect()
            MsgBox("Connection Successful As " + TextBox1.Text, MsgBoxStyle.Information)
            TextBox1.Clear()
            TextBox3.Clear()
        End If
End Sub

Next, enter the following code in the Form_Closing event

Private Sub Form1_FormClosing(ByVal sender As System.Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles MyBase.FormClosing  
        writeSocket("DIS:")
        If Not (clientThread Is Nothing) Then
            If clientThread.IsAlive Then clientThread.Abort()
        End If
        If Not (reader Is Nothing) Then
            reader.Close()
        End If
        If Not (writer Is Nothing) Then
            writer.Close()
        End If
        If Not (client Is Nothing) Then
            client.Close()
        End If
        Me.Dispose()
End Sub

Now, we have finished on the server part, now we move on client project. Same as server, create a module and name it TCPcontroller, then enter the following code

Imports System.IO
Imports System.Net
Imports System.Net.Sockets

Public Class TCPcontroller
    Public client As TcpClient
    Public clientData As StreamWriter

    Public Sub New(ByVal Host As String, ByVal Port As Integer)   
        On Error Resume Next
        client = New TcpClient(Host, Port)
        clientData = New StreamWriter(client.GetStream)
    End Sub

    Public Sub send(ByVal Data As String)
        On Error Resume Next
        clientData.Write(Data & vbCrLf)
        clientData.Flush()
    End Sub
End Class

Next, go to the form section, then import some of the required libraries

Imports System.Drawing.Text
Imports System.Net.Sockets
Imports System.Text
Imports System.IO
Imports System.Net

Public Class Form1

End Class

Then, declare the following global variables

Public Class Form1
    Private Declare Function mciSendString Lib "winmm.dll" Alias "mciSendStringA" (ByVal lpstrCommand As String, ByVal lpstrReturnString As   
    String, ByVal uReturnLength As Integer, ByVal hwndCallback As Integer) As Integer
    Private clientnya As TCPcontroller
    Dim FileName As String
    Dim pfc As New PrivateFontCollection()
    Dim status As Byte
    Dim clientThread As System.Threading.Thread
    Dim client As New TcpClient
    Dim screen As Screen
    Dim reader As BinaryReader
    Dim writer As BinaryWriter
    Dim message As String
    Dim username As String
    Delegate Sub updateMessageDelegate(ByVal message As String)
End Class

Then, make some of the following functions

Sub updateMessageWork(ByVal message As String)
        RichTextBox1.AppendText(message + vbNewLine)
    End Sub
    Sub updateMessage(ByVal message As String)
        If RichTextBox1.InvokeRequired Then
            Invoke(New updateMessageDelegate(AddressOf updateMessageWork), message)
        Else
            RichTextBox1.AppendText(message + vbNewLine)
        End If
    End Sub
    Sub startConnect()
        Try
            client = New TcpClient()
            client.Connect(IPAddress.Parse(TextBox3.Text), 8888)
            reader = New BinaryReader(client.GetStream())
            writer = New BinaryWriter(client.GetStream())
            writer.Write("USR  " & TextBox2.Text)
            username = TextBox2.Text
            clientThread = New System.Threading.Thread(AddressOf readSocketClient)     
            clientThread.Start()
        Catch ex As Exception
            Exit Sub
        End Try
    End Sub

    Public Sub readSocketClient()
        While True
            Try
                message = reader.ReadString()
                If message.Substring(0, 3) = "MES" Then
                    updateMessage(message.Substring(4))

                End If
                If message = "err" Then
                    MsgBox("Problem Connection", MsgBoxStyle.Information, "Information")
                    message = reader.ReadString()
                    End
                End If
            Catch e As Exception
                Exit While
            End Try
        End While
    End Sub

    Public Sub writeSocket(ByVal message As String)
        Try
            If client.Connected Then
                writer.Write(message)
            End If
        Catch ex As Exception
            Exit Sub
        End Try
    End Sub

Next, double-click the Sign In Button and enter the following code

Private Sub ButtonSignIn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ButtonSignIn.Click   
        If ButtonSignIn.Text = "SIGN IN" Then
            If TextBox2.Text = "" Or TextBox3.Text = "" Then
                MsgBox("please complete all fields", MsgBoxStyle.Exclamation)
            Else
                clientnya = New TCPcontroller(TextBox3.Text, 8080)
                startConnect()
                ButtonSignIn.Text = "SIGN OUT"
                ButtonSignIn.FlatAppearance.MouseOverBackColor = Color.Red
                MsgBox("You Are Connected As " + TextBox2.Text, MsgBoxStyle.Information)
                TextBox2.Clear()
                TextBox3.Clear()
            End If

        Else
            writeSocket("DIS:")
            If Not (clientThread Is Nothing) Then
                If clientThread.IsAlive Then clientThread.Abort()
            End If
            If Not (reader Is Nothing) Then
                reader.Close()
            End If
            If Not (writer Is Nothing) Then
                writer.Close()
            End If
            If Not (client Is Nothing) Then
                client.Close()
            End If
            MsgBox("You Sign Out", MsgBoxStyle.Information)
            ButtonSignIn.Text = "SIGN IN"
            ButtonSignIn.FlatAppearance.MouseOverBackColor = Color.Green
        End If
End Sub

Next, double-click the send button and enter the following code

Private Sub ButtonSent_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ButtonSent.Click   
        If ButtonSent.Text = "SIGN IN" Then
            MsgBox("You Must Sign In First", MessageBoxIcon.Exclamation)
        Else
            If TextBox1.Text = "" Then
                MsgBox("Message Can not Empty.", MessageBoxIcon.Exclamation)
            Else
                writeSocket("MES:" & username & " : " & TextBox1.Text)
                TextBox1.Text = ""
                TextBox1.Focus()
            End If
        End If
End Sub

and finally, enter the following code in the Form_Closing event

Private Sub Form1_FormClosing(ByVal sender As System.Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles MyBase.FormClosing  
        writeSocket("DIS:")
        If Not (clientThread Is Nothing) Then
            If clientThread.IsAlive Then clientThread.Abort()
        End If
        If Not (reader Is Nothing) Then
            reader.Close()
        End If
        If Not (writer Is Nothing) Then
            writer.Close()
        End If
        If Not (client Is Nothing) Then
            client.Close()
        End If
        Dispose()
End Sub

Up here, the program is ready to run using one device. If you want to use multiple devices, do not forget to change the IP Address of the device you want to use

For more details, please watch the video below