New form becomes unresponsive.

[Ryan0589]

I've recently just started looking into TCP sockets for Server-Client communications in VB.Net(VS2010); which I have working fine whilst on a single form. However, when I try to load another form it calls the form_load part and runs that part, but then appears as if it's in an endless loop on the original form because the mouse turns to time out whilst on the new form. Anybody know a solution on how to solve this?


Client side Login form(works fine and is responsive)

Public Class Login
    Private client As System.Net.Sockets.TcpClient
    Private Const BYTES_TO_READ As Integer = 255
    Private readBuffer(BYTES_TO_READ) As Byte
    Public UName As String



    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        client = New System.Net.Sockets.TcpClient("172.16.3.9", 43001)
        client.GetStream.BeginRead(readBuffer, 0, BYTES_TO_READ, AddressOf doRead, Nothing)

    End Sub
    Private Sub doRead(ByVal ar As System.IAsyncResult)
        Dim totalRead As Integer
        Try
            totalRead = client.GetStream.EndRead(ar) 'Ends the reading and returns the number of bytes read.    
        Catch ex As Exception
            'The underlying socket have probably been closed OR an error has occured whilst trying to access it, either way, this is where you should remove close all eventuall connections     
            'to this client and remove it from the list of connected clients.     
        End Try
        If totalRead > 0 Then


            'the readBuffer array will contain everything read from the client.     
            Dim receivedString As String = System.Text.Encoding.UTF8.GetString(readBuffer, 0, totalRead)
            messageReceived(receivedString)

        End If
        Try
            client.GetStream.BeginRead(readBuffer, 0, BYTES_TO_READ, AddressOf doRead, Nothing) 'Begin the reading again.   
        Catch ex As Exception
            'The underlying socket have probably been closed OR an error has occured whilst trying to access it, either way, this is where you should remove close all eventuall connections           
            'to this client and remove it from the list of connected clients.        
        End Try
    End Sub
    Private Sub messageReceived(ByVal message As String)


        If message = "Connected" Then
            MessageBox.Show("Welcome " & Username.Text)

            MainScreen.Show()

            MainScreen.Focus()



        End If
    End Sub
    Private Sub SendMessage(ByVal msg As String)
        Dim sw As IO.StreamWriter
        Try
            sw = New IO.StreamWriter(client.GetStream)
            sw.Write(msg)
            sw.Flush()
        Catch ex As Exception
            MessageBox.Show(ex.ToString)
        End Try
    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Submit.Click
        Dim strMes As String
        strMes = "CONNECT|" & Username.Text & "|" & Password.Text & ChrW(13)
        UName = Username.Text
        SendMessage(strMes)
    End Sub

    Private Sub RectangleShape1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)

    End Sub

    Private Sub RichTextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles RichTextBox1.TextChanged

    End Sub

    Private Sub Cancel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Cancel.Click
        SendMessage("DISCONNECT|")
        End
    End Sub
End Class

Mainscreen form(client side) unresponsive after its initially loaded from call within Login form:

Public Class MainScreen

    Private Sub MainScreen_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
       

        TreeView1.Nodes.Add("Users2")

        TreeView1.Nodes(0).Nodes.Add("User3")



    End Sub
End Class

Tried breakpointing to find out where the loop appears to be and I think its in the doRead sub.

 

[JohnH]

add this:

Delegate Sub ReceivedHandler(ByVal text As String)

and swap this:

messageReceived(receivedString)

with this:

Me.Invoke(New ReceivedHandler(AddressOf messageReceived), receivedString)

 

[Ryan0589]

Thank you very much JohnH, foolish of me really as I had the invoke part on the server side.

Either way very clearly and succintly put, thank you! .

 

[rihannajones]

ya facing same problem......