TCP Connection and DesktopView

[Aowin]

Hi guys,
i have a desktop viewer but i need to close the tcp connection and connect to other.
How can i do this?

Here is my codes:

Imports System.Net.Sockets
Imports System.Threading
Imports System.Drawing
Imports System.Runtime.Serialization.Formatters.Binary

 Dim client As New TcpClient
 Dim nstream As NetworkStream

Public Function Desktop() As Image
        Dim bounds As Rectangle = Nothing
        Dim screenshot As System.Drawing.Bitmap = Nothing
        Dim graph As Graphics = Nothing
        bounds = Screen.PrimaryScreen.Bounds
        screenshot = New Bitmap(bounds.Width, bounds.Height,        System.Drawing.Imaging.PixelFormat.Format32bppArgb)
        graph = Graphics.FromImage(screenshot)
        graph.CopyFromScreen(bounds.X, bounds.Y, 0, 0, bounds.Size, CopyPixelOperation.SourceCopy)
        Return screenshot
    End Function

    Private Sub ResimGönder()
        Dim bf As New BinaryFormatter
        nstream = client.GetStream
        bf.Serialize(nstream, Desktop())
    End Sub

Imports System.Net
Imports System.Net.Sockets
Imports System.Threading
Imports System.Drawing
Imports System.Runtime.Serialization.Formatters.Binary

Dim client As New TcpClient
    Dim server As New TcpListener(8085)
    Dim nstream As NetworkStream
    Dim Listening As New Thread(AddressOf Listen)
    Dim getImage As New Thread(AddressOf receiveImage)

Private Sub receiveImage() ' gelen ekran görüntüsünü PictureBox a yansıtıyoruz
        On Error Resume Next
        Dim bf As New BinaryFormatter
        While client.Connected = True
            nstream = client.GetStream
            PictureBox1.Image = bf.Deserialize(nstream)
        End While
    End Sub

    Private Sub Listen()
        While client.Connected = False
            server.Start()
            client = server.AcceptTcpClient
        End While
        getImage.Start()
    End Sub

Thanks

[passel]

Well, I assume the first code block is the client, but I don't see where you connect to the Server or who calls ResimGönder().
Which side do you want to initiate the disconnect?
I assume if you had something in the code on the client side that we can't see that would not call ResimGönder() but instead close the connection, then on the server side your While loop in receiveImage might exit.
If the while loop exits then it seems you should be able to start another instance of the Listening thread before you exit the receiveImage() sub/thread.

    Private Sub receiveImage()  ' ....
'...
        End While
        Listening = New Thread(AddressOf Listen)
        Listening.Start()
    End Sub

You could then start another client on another machine to connect to the server which should be listening.

The way I've done it in the past (on the server side, with a single connection) is have a nested loop and only one thread.
The thread would enter the outer loop and Listen for the connection.
Once a connection was made it would enter the nested (inner) loop and continually read and process the stream.
This inner loop was wrapped inside an exception handler.
If the connection closed normally, or broke for some other reason, causing an exception, the inner loop would exit, the current connection closed, and the outer loop would loop back and we would be back listening for a new connection.

[Aowin]

Oh sorry.

client:

Imports System.Net.Sockets
Imports System.Threading
Imports System.Drawing
Imports System.Runtime.Serialization.Formatters.Binary

 Dim client As New TcpClient
 Dim nstream As NetworkStream

Public Function Desktop() As Image
        Dim bounds As Rectangle = Nothing
        Dim screenshot As System.Drawing.Bitmap = Nothing
        Dim graph As Graphics = Nothing
        bounds = Screen.PrimaryScreen.Bounds
        screenshot = New Bitmap(bounds.Width, bounds.Height,        System.Drawing.Imaging.PixelFormat.Format32bppArgb)
        graph = Graphics.FromImage(screenshot)
        graph.CopyFromScreen(bounds.X, bounds.Y, 0, 0, bounds.Size, CopyPixelOperation.SourceCopy)
        Return screenshot
    End Function

    Private Sub ResimGönder()
        Dim bf As New BinaryFormatter
        nstream = client.GetStream
        bf.Serialize(nstream, Desktop())
    End Sub

 Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
        Try
            client.Connect("127.0.0.1", "80")
            MsgBox("client connected!", vbInformation, "")
        Catch ex As Exception
            MsgBox("failed to connect!", vbInformation, "")
        End Try
    End Sub
Private Sub Button2_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click
        timer1.start()
    End Sub

    Private Sub Timer1_Tick(sender As System.Object, e As System.EventArgs) Handles Timer1.Tick
        ResimGönder()
    End Sub

    Private Sub Button3_Click(sender As System.Object, e As System.EventArgs) Handles Button3.Click
        client.Close()
        Timer1.Stop()
    End Sub

Server:

Imports System.Net
Imports System.Net.Sockets
Imports System.Threading
Imports System.Drawing
Imports System.Runtime.Serialization.Formatters.Binary

Dim client As New TcpClient
    Dim server As New TcpListener(8085)
    Dim nstream As NetworkStream
    Dim Listening As New Thread(AddressOf Listen)
    Dim getImage As New Thread(AddressOf receiveImage)

Private Sub receiveImage() ' gelen ekran görüntüsünü PictureBox a yansıtıyoruz
        On Error Resume Next
        Dim bf As New BinaryFormatter
        While client.Connected = True
            nstream = client.GetStream
            PictureBox1.Image = bf.Deserialize(nstream)
        End While
    End Sub

    Private Sub Listen()
        While client.Connected = False
            server.Start()
            client = server.AcceptTcpClient
        End While
        getImage.Start()
    End Sub

Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
        listener = New TcpListener(80)
        Listening.Start()
    End Sub

I tried like you said ; "End of Stream encountered before parsing was completed."

[passel]

I wasn't even aware the "On Error Resume Next" was even available in .Net because I've never used it.
That isn't handling the exception, it is ignoring it.
I was thinking a Try Catch like you have in other parts of your code.

Since you need to restart, i.e. recreate threads and objects, rather than create some thread or objects in the declarations, they should be declared in the code before use so that when you restart that portion of code it can create new instances of the object or threads.
I made a couple of changes in the code because they were flagged because I always have Option Strict on by default.
I went ahead and recreated the projects with your code so I could test the changes.
This works, but feels a bit awkward, but I'm not going to try to suggest more than I have already. So below is just my changes to your existing code work for me, along the lines of what I was thinking in my previous post.

Imports System.Net
Imports System.Net.Sockets
Imports System.Threading
Imports System.Drawing
Imports System.Runtime.Serialization.Formatters.Binary

Public Class ClientForm
  Dim Client As TcpClient
  Dim nstream As NetworkStream

  Public Function Desktop() As Image
    Dim bounds As Rectangle = Nothing
    Dim screenshot As System.Drawing.Bitmap = Nothing
    Dim graph As Graphics = Nothing
    bounds = Screen.PrimaryScreen.Bounds
    screenshot = New Bitmap(bounds.Width, bounds.Height, System.Drawing.Imaging.PixelFormat.Format32bppArgb)
    graph = Graphics.FromImage(screenshot)
    graph.CopyFromScreen(bounds.X, bounds.Y, 0, 0, bounds.Size, CopyPixelOperation.SourceCopy)
    Return screenshot
  End Function

  Private Sub ResimGönder()
    Dim bf As New BinaryFormatter
    nstream = Client.GetStream
    bf.Serialize(nstream, Desktop())
  End Sub

  Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
    Try
      Client = New TcpClient
      Client.Connect("127.0.0.1", 8085)
      MsgBox("client connected!", vbInformation, "")
    Catch ex As Exception
      MsgBox("failed to connect!", vbInformation, "")
    End Try
  End Sub
  Private Sub Button2_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click
    Timer1.Interval = 250
    Timer1.Start()
  End Sub

  Private Sub Timer1_Tick(sender As System.Object, e As System.EventArgs) Handles Timer1.Tick
    ResimGönder()
  End Sub

  Private Sub Button3_Click(sender As System.Object, e As System.EventArgs) Handles Button3.Click
    Client.Close()
    Timer1.Stop()
  End Sub
End Class

Imports System.Net
Imports System.Net.Sockets
Imports System.Threading
Imports System.Drawing
Imports System.Runtime.Serialization.Formatters.Binary

Public Class ServerForm
  Dim client As New TcpClient
  Dim server As New TcpListener(8085)
  Dim nstream As NetworkStream
  Dim Listening As New Thread(AddressOf Listen)
  Dim getImage As Thread

  Private Sub receiveImage() ' gelen ekran görüntüsünü PictureBox a yansıtıyoruz
    Dim bf As New BinaryFormatter
    Try
      While client.Connected = True
        nstream = client.GetStream
        PictureBox1.Image = CType(bf.Deserialize(nstream), Image)
      End While
    Catch ex As Exception
    Finally
      If nstream IsNot Nothing Then nstream.Dispose()
      client.Close()
    End Try
    Listening = New Thread(AddressOf Listen)
    '  server.Start()
    Listening.Start()
  End Sub

  Private Sub Listen()
    While client.Connected = False
      server.Start()
      client = server.AcceptTcpClient
    End While
    getImage = New Thread(AddressOf receiveImage)
    getImage.Start()
  End Sub

  Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
    Listening.Start()
  End Sub
End Class