i made a simple tcp listener server.Now I can use my client to connect,it connets, everything is good. The
problem is when I open the first client, then I open another one, it doesn't connect. It accepts only 1.Any way I can accept multi connections?
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I am working on a remote administration tool. But I have a problem, since the server connects to the client the client needs a tcplistener. But when the client starts too listen the program freezes and I can't do anything. The reason is that the tcplistener runs in a loop which freezes the form. What shall I do too fix the program?
View 1 RepliesBasically, in my Tcp Library I'm working on, whenever the system is told to "Stop", the OnClientConnected() Routine fires off, which is only raised under two circumstances: When a Client connects (obviously) When the server is told to shutdown
Now, the first one is handled just fine. But the second one is not. In fact, it has caused me a great deal of headache because it keeps throwing exceptions on this line in particular:
Dim _tcpClient As System.Net.Sockets.TcpClient = _tcpListener.EndAcceptTcpClient(IR)
When I hover over while debugging, I can see a few members that reveal exception data I could utilize; but unfortunately those members are private and I don't want to utilize reflection unless I have to since it could slow down performance where there may not be a real reason to.
I have thought of writing in a Boolean check to see if the server received a shutdown signal and that would indicate that it's time to not accept anything, but I want to avoid that if possible.
Is there any way to see if the TcpListener is no longer accepting connections and has had .Stop() called without reverting to catching the ObjectDisposedException that is raised? (because the Socket that is "accepted" is actually a disposed one)
I'm trying to execute a sub with multiple parameters on a separate thread, but I just can't get it to work, Here's my code
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I have this code to connect to my server:
client = New TcpClient(txtIP.Text, txtPort.Text)
client.GetStream.BeginRead(readBuffer, 0, BYTES_TO_READ, AddressOf DoRead, Nothing)
SendMessage("/CONNECT|" & Label25.Text)
How do I check if the TcpListener is available?
I am creating an application that will be talking over the LAN (and eventually, WAN) which uses the Tcplistener and Tcpclient objects.Now, I have this working absolutely fine locally using the loopack address although when I change the IP of the listener to 0.0.0.0 (listening for all IPs) and the IP in the client application, to the IP of the server, it throws an exception when connecting. The client says something along the lines of the the server has rejected the incoming connection. So i disabled all firewalls temporarily but I still have the problem.I have ran netstat on the server which clearly shows that it is listening for an incoming connection on 0.0.0.0. [code]
View 5 RepliesOne to accept only file word and pdf file and the other to accept only images(.jg|.bmp|.png|.gif)
View 1 RepliesI've written a simple WAV player in VB 2010 - a Windows Form App with no menus. I'm trying to create a hotkey, like CTRL-D that would make a text box visible. Typing the correct password in the box will expand the form and show some Administrative functions. I'm having issues creating the hotkey with more than one key.I've got the following code, but it does not work. I do have KeyPreview set to True.
Private Sub _KeyDown(sender As Object, e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyDown
If e.KeyCode = Keys.Control And e.KeyCode = Keys.D Then
txtPWD.Visible = True
I've also tried
If e.Keycode = Keys.ControlKey & e.KeyCode = Keys.D
and many other variations including changing to ALT and SHIFT but nothing seems to work. If I remove one of the Keys, it works just fine.
I've been raking my brain for quite some time on this. Is there any way with VB.NET that I can use multiple IP's in one instance of a program? For example, I want to be able to navigate to a web page 10 times at once, with each one using a different IP. I want them to be parallel (multi-threaded) rather than going sequentially. Going sequentially, I could just do the action, change the IP, do the action, change the IP.
View 5 RepliesHow do i go about multi-threading that, it's just an example project, so i can try and learn from it. As i'm having a hard time understanding JMC's tutorial as it doesn't directly relate to what i'm trying to do [code]When you hit 'Start', the start button is disabled and the Label1 then changes to "Downloading".The data is then downloaded and put into the Textbox1.Label then reads "Complete" Start button is enabled.
View 5 RepliesI have a button and when it's clicked a HTTP request is sent out to a website to do a few things, but because its got to load the external resources it makes the interface frozen. I've moved the HTTP onto another thread using the follow
VB.NET Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim Thread1 As New System.Threading.Thread(AddressOf check_accounts)
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When i want to update a label that is on my main form (from the check_accounts sub). I know that isn't the right way, but i have no idea what the right way is. All the documentation i can find is very (excuse me for this) nerdy and really doesn't offer much insight on how to incorporate it into a project.
I want to be able to have a numericupdown box that can let the user change the amount of threads they want to use. I assume more threads allow the http requests to be done faster and at the same time?Also if i wanted to pause the HTTP requests, would the best method to use be pausing the thread?
I have this code to connect to my server:
client = New TcpClient(txtIP.Text, txtPort.Text)
client.GetStream.BeginRead(readBuffer, 0, BYTES_TO_READ, AddressOf DoRead, Nothing)
SendMessage("/CONNECT|" & Label25.Text)
[code].....
How do I free an instance of TcpListener?
How, in VisualBasic, to I delete something from a 'new'?[code]...
I have an application that listens for connections asynchronously. When a connection comes in, it spawns a new thread from the callback method. This works fine for up to about 13 simultaneous connections then it dies with an out of memory error. The threads that are spawned just do a CHAP handshake and authenticate then go in to a command loop where they sleep until a command comes in or a timeout occurs. I have pasted the code below. Sometimes it will not throw an error but the thread never gets spawned although the connection is accepted.
Code:
Imports System.Net.Sockets
Imports System.Threading
Public Class UpdateMonitor
[Code]....
I have just created a website server with Visual Basic 2008. I want my server to have the famous "resume donwload" function... but i dont know how the HTMLHeader should look like when its resuming a download.
Here is how the header normaly looks:
HTMLHeader = _
"HTTP/1.0 200 OK" & ControlChars.CrLf & _
"Server: Website Server " & My.Application.Info.Version.ToString & ControlChars.CrLf & _
"Content-Length: " & GetFileSize & ControlChars.CrLf & _
"Content-Type: " & GetContentType(StringRequest) & _
ControlChars.CrLf & ControlChars.CrLf
I'm using Regex.Replace function. It fails to accept trackbar1.value as "replacement as string". This code returns "Reference to a non-shared member requires an object reference." error:
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In my football sim I am trying to save all the info from a game. There are two defined dimensions to this array. The first is the number of weeks(17 always) and then the number of games per week (Number of teams /2). The plays themselves are unknown in quantity so I decided to use List of to store them. With this type of multi-dimensional array that is also a List of I am having trouble with the Get and Set properties. I have a member variable declared as:
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I am a Network Administrator in the Army so programming is not my strong area. I have been messing with Batch files and WMI, just recently i started VB Scripts (VERY BASIC) like adding an input box to set computer name, scan network for computer name on domain, return wmi info for that remote computer etc... I know there are programs out there that can do all of this, however the Army will only allow certain approved programs to be installed on government workstations, i have been using .Bat files to gather info which is fine, however it is very time consuming when you have entire subnets with computers, networked printers, etc to place into a spreadhseet for higher headquarters tracking not to mention the over 20 columns of required data to track for each computer. I have VB 2010 Express, working on a Windows Form Application Project. Goal is to interface my VB Script (written with notepad) with a GUI that will generate an internal spreadsheet on the form window in a datagridview. So far i have the basic window and i have my gridview with my column headers set. How do i get the data into the columns and rows accordingly.
Application Basic: Execute Program, in main window select button (Scan IP Range) <--- I want this to open an input box for the beginning subnet, input base address to start scan from, next input box for end range, then msgbox for start scan. i want the results of the scan to autofill the datagridview and add new row for each IP address that had a ping reply, returning valid data from WMI results as it receives the data. What would be the best method to achieve my goal. i am not asking you to write the program, i have been looking and studying MULTIPLE sites, think i just need another set of eyes on this to unlock the knowledge i have locked away, if ya know what i mean. Also, if you don't mind let me know what you think of this app im trying to turn out... Super Thanks for your help.This is the Base Batch File running. It calls an external VB Script written in notepad. (I want this implemented into the app form so there is no console window.)This is the inputbox from external VB Script that is called.This the result of the external VB Script (the info i want to put in the datagridview of the app.)I also, for some reason can't get scroll bars to show in the app when i hit F5, theres about 15 columns passed the MAC column...?
I have a string, which can easily be splitted by seperators into an array.The output has to be splitted again an move into a multi-dimensional array (2nd index)[code]
View 2 RepliesI am working on an application that is taking pretty long to execute. I started playing with mutli-threading and it seems to have greatly sped up my app. Problem is that threads are still executing and the rest of the code executes before the threads finish. Here is my
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I'm having some issues with parsing a lot of information into controls using winforms. I've tried adding threads/backgroundworkers, but they don't seem to work properly. To avoid the cross-thread exception, I had to add an invocation checker:If Me.InvokeRequired Then Me.Invoke(New MethodInvoker(AddressOf ParseSub()))This just freezes the form as it would without threading, but without the invoke checker I get cross thread exceptions because information from one thread is trying to be sent to another.
View 6 Repliesi have a script with a login form that creates a folder per user with username.txt, password.txt, firstname.txt, and lastname.txt. - auto creates when creating new user.after i log in and change form i want an label showing the first and last name of the person logged in,how am i supposed to do that? is there any way to make like an "admin" form where new account applies will pop-up when "admin" log in and then either accept or reject new users?
View 8 RepliesI'm adding multi-threading facilities for the first time. I have a function that is wrapped to be run in a separated thread. This function retrieves data (text) from a combobox and it works for sure without multi-threading.
When I call it as multi-threaded, I get the following error when I try to retrieve the data from the cmobobox: Cross-thread operation not valid: Control 'cmb1stBL' accessed from a thread other than the thread it was created on.
It looks like a restriction of thread-safety... I assume that the child thread cannot read from his parent, to make sure that he doesn't change his parent data. So how can I read the data from the combobox? Should I read the comoboxbox data before calling the child thread?
I have a need to build an app that will access about 10 websites and pass data to them, etc.I've read about something called multi-threading when searching Google. I've also seen people say that they use multiple browsers.Which route is better to use? I figure if you have to do some sort of multi-threading that you would access a single browser?
View 2 RepliesHow can I detect when a client disconnects from the TcpListener ?
Each of my clients is handled in a separate thread.
Is it necessary to close the connection of a tcplistener or tcpclient after every message received, or is it possible to close it at a later time while it continues to receive data? Is there any major security issue with leaving it open and listening? I know trojans tend to open a listener and leave it open, will my program be detected as such? Its just a simple chat program....
View 1 Replies[code]I send the Thread via Thread.Sleep to sleep mode when nothing happens here. Does this affect the TCPListener in his work somehow and what happens to an incomming connection while the Thread is in sleep-mode?
View 3 RepliesI have been programming a TcpListener Program and I have everything working right! So far... Except that when I have multiple clients connecting to my Server... I used a try catch statement to catch the error and it says that tcplistener doesn't allow multi connections... think creating a new thread for each connection sounds like the most reasonible answer but I can't grasp the concept of it...
Here is my frmMain:
Imports System.IO
Imports System.Net
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I posted this code in another thread as an example of how to listen for connecting clients using TcpListener.it is a small part of a larger project, its all my own work,
Imports System.Net
Imports System.Net.Sockets
Public Class Server[code].....
How can I ask my tcpListener to listen to particular IP on specific port? I want my tcpListener to listen to the local IP of the machine. I can get the ipaddress of the pc using Dns.GetHostAddresses(). But, if pc have multiple ip's how can I know which ip address is correct? From tcpClient class I am connecting to the server. So, I know the server ip and so I want to specify ipaddress to my tcpListener class to listen on.
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