I am trying to use the code from Microsoft for an Async Socket connection. It appears the listener runs in the main thread locking the GUI. I am new at both socket connections and multi-threading all at the same time. Having a hard time getting my mind wrapped around this all at once.
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I coded a small tcp server/client software implementing the async methods of the socket object. In order to keep track and control of the transfered data on both sides, I decided to wrap the bytes to be transfered into small 65 000 bytes packets, sent one after each other, in varying order.In most cases, it works perfectly, and it is impressively fast. However, when I want to transfer larger data than my usual requests, say like a dozen megabytes, crippling problems start to appear, out of shit.Effectively, it seems that somehow when executed without pauses, the server sends the packets too fast, or that the client receives it too slowly. However, if I put the SendAsync method's thread to sleep for like 100ms before sendingthe next packet, everything arrives without problem on the client.[code]
View 1 RepliesI wrote a Socket Client which will send the Socket Server some data and get some response from Server. This process will be running once in every 2 seconds.
Now what I need to know is How we can identify the connection lost between Server and Client?
I need this to be implemented in the Client side. If there is no connection then Client should automatically close the connection. Once the connection with the server is available in the next attempt it should connect automatically.
I have been developing an async socket connection server and client program. I have been testing it, and noticed that if I connect to the server from my client and then disconnect. Upon reconnecting I am on a different port(local IP still). This is fine, however when I go to send a message, and the server trys to update all the clients, it eventually hits clients that do not exist anymore. I get the SocketException 10054, and upon connecting/disconnecting enough, it no longer works at all. My question is how do I clear out these no longer useful sockets from the server? I am doing currentsocket.Shutdown(SocketShutDown.Both); and then a currentsocket.Close(); after that. When a user disconnects.
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I have my index.aspx file:
<%@ Page Language="vb" AutoEventWireup="false" CodeBehind="index.aspx.vb" Inherits="Web_Socket.index" %>
<!DOCTYPE html>
<html>
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so now my question is how do i connect the WebSocketServer.cs to the index.aspx ?
As a start, all I'm trying to accomplish is just to get the Web Sockets working, and have the connection established, which then will alert("Stock Ticker Connection open ...");
I am using socket programming in vb.net to create a server client remoting application. The problem occurs when I use both the client and server in a win 7 box. It works fine for win xp or cross-platform communication (e.g. win xp to win 7). Below are the codes used at the client and server end:
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I'm working on an application that communicates to torque controllers on the factor floor. The user inputs an IP address and a port and clicks the btnConnect button to make the initial connection. Once that completes a KeepAlive message must be sent periodically to maintain communication with the torque controller. The initial connection works very well but a socket error (see below) grinds everything to a halt when the KeepAlive message is sent. I would appreiciate any ideas the readers may have on the root cause. I'm quite confused because basically the same code is use for both the initial connection and then the KeepAlive messages. I have pasted some of the code as well below.
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I am trying to make a class that will allow me to open a socket, leave it open and then write to it when needed. I wrote the following code but whenever I call the writeData sub I get an error with the network stream. Its says it is not an open connection. I call the connection sub first and then the writeData sub.
Imports System.Net.Sockets
Imports
System.Text
Public
Class vizSocketConnect
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I have codes which is written with python. I am not good with python and i want to convert this python codes to VB 2010.This python function searching local network and finding my LG TV's local IP adress. I want to find my TV's local IP with VB 2010.
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Am developing a server - client application using the system.net class , that will have more than 5000 simultenous client connection.what is the best way to manage multiple client connection like this?
View 3 RepliesI converted some codes from python to VB 2010. My aim is sending query data to multicast IP and get the response. My query data receiving from device which is connected to my LAN. Also the device responding my query and my PC receiving the responce but at this point the VB program freezing.getting response data and printing to console without freezing.
This is the code list;
Imports System.Net
Imports System.Net.Sockets
Imports System.Text
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Here is the Wire Shark (Network Protocol Anlyzer) screen shots; My computer IP is : 192.168.0.11 and device's IP is : 192.168.0.10.
I have the following code in my Server Form:
Imports System.Net, System.Net.Sockets
Public Class ServerForm
Private serverSocket As Socket
Private clientSocket As Socket
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for the first time, when I click on Connect, it is going to connect to server as well and also it works if you click on the disconnect. for the second time if you click on the Connect button, it gets connected but the disconnect button is not working.
i need a little advice/help here. There is a particular scenario that is coming up and I am clueless as to how to go about it."I will soon have a lease line through which I will get realtime stock market data. This data will be available every second and it will contain prices of stocks. Now assume I am able to get that data on my local computer. How can I transmit data so that users can get that data through my software.
For e.g. assume it's 11 AM. Now if you select a stock e.g. Google, then my program should fetch data for google till 11 AM and also show new data every second or so with minimum lag. Something like a terminal where you see stock prices getting updates every second. In my case I need to get past data and show current data which get updated at short intervals."
Now I have a linux vps webserver which hosts my site. (I get one or two static ip free) What to do so that data goes from my local computer to my server and then my program (developed in vb.net) is able to get it and show it to end user. This whole system should such that its fast (real-time) and delay is minimum.
im trying to detect if the connection is still active upon trying to send or receive anything. Now I have checks in place if it's connected then it will send or receive however... it's saying it's connected when it is not connected... and therefore my program tries to send and receive and errors.
I am determining if it is ok to send and receive by using the Socket.Poll(-1, SelectMode.SelectWrite)
if it's true then im connected and data can be passed..This seems to always be true until I send something and it fails..How can I catch the socket not being connected before it fails upon sending or receiving?
I am an absolute beginner on ASP.net (VB.) Please pardon me if the question is too obvious for the experienced members.I tried to make a simple WebRequest in the async mode in case the target URL takes long to provide the data. In my code below, I just want to see if the callback block (RespCallback) is called correctly every time. If all goes well, lblResult should have the string '123' appended to it every time I click the button which calls the 'GetData' sub.
However, the lblResult only shows 123 after the first click. After the subsequent click, the lblResult only gets appended with '12', as if RespCallback is never called. When I tried to debug this in Visual Studio, the execution actually stepped right into the RespCallback part and the lblResult.Text watch actually shows '123123' but the resulting Web page always shows only '12312'
I am sure I am missing something basic here, but I just don't know what. I was even guessing that it has to do with browser cache (hence the result changes for the second time) but I don't know how to fix that either.
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For almost a week I am reading and trying to find a solution for checking connection state using a TCP Client (using socket class) In my scenario I have a TCP Client that is connected to a server (it is not controlled by me) and i want that from time to time to check the connection state, and reconnect if necessary.I have read a lot of information on the internet but i did not find a suitable solution.Briefly, these are the methods that i have found on the internet and try to implement.But unfortunatelly, i have found some scenarios where the TCP Server is closed and the TCP Client is still saying Connected 1.Example from MSDN
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I would like to know can we use a socket connection on vb to communicate with PC without using GSM modem and SIM card.for example, like sendin a simple text msg to the PC and it will reply back the result back to me the result.
View 1 RepliesI want both the client and server to write and read resp. at a constant rate (which can be configured on the GUI of the client) to the buffer.I am able to send from the client at 150 bytes per packet Now, I should be able to read also at 150 bytes per packet on the server too Since, both are connected through a socket, can we retrieve the socket params (set on the client size, like 150 here) from the server end, using the tcpServer object.Or is it must to send an initial setup packet which tells about these client params and so accordingly the server can continue?
View 1 RepliesI'm trying to write a 'developer friendly' wrapper for the Windows API EnumWindows - the problem is that the API uses a callback function that gets invoked on another thread, where as I want my wrapper function to simplify this and make it more useful by working like any other normal synchronous function and just returning a value.
Now if the API just called the callback once that would be fine, as I would just call the API and make the wrapper function wait until it got a signal from the callback function telling it to continue... but the API calls the callback function over 100 times (once for every window handle that exists). The biggest problem is that there is nothing that indicates that any particular call to this callback function is the last one, so my wrapper function has no idea when it is safe to continue and return the list of window handles to the caller.
The only solution I could think of is to do this:
1. The wrapper function calls the API and starts a timer that waits 2 seconds before it raises the Elapsed event. The wrapper function then pauses until it receives a signal (ManualResetEvent)
2. Each time the callback function is raised by the API on a different thread, it stops the timer (so this is before the 2 seconds have elapsed), adds the current window handle that was passed in by the API to the list of handles, then starts the timer again.
3. If the timer reaches its 2 second interval then it is assumed that we are at the end of the windows because otherwise the callback would have stopped the timer. So the timer's Elapsed event handler is what signals the original thread (that the wrapper function is executing on) to continue as we now have a complete list of windows to return.
This works fine and does exactly what I want... but I dont like it.
I dont like forcing the caller to wait an extra 2 seconds after the API has done its last callback but more importantly I dont like assuming that the API will never take longer than 2 seconds between callbacks. In reality on my PC it is never anywhere near that long between callbacks, it is something like 200 miliseconds, but I have no idea how long it would be on a slower PC and I want this to be completely reliable.
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I am trying to coonect to Oracle 10g database through ASP using ODBC connection. The connection string used is con.Open "DRIVER={Microsoft ODBC for Oracle};SERVER=xxxx;UID=xxxxx;PWD=xxxxx".
This works when I tried creating a macro and also using a vbs script. When run through classic ASP it gives error on the connection.open line.
Microsoft OLE DB Provider for ODBC Drivers error '80004005'. [Microsoft][ODBC driver for Oracle][Oracle]Error while trying to retrieve text for error ORA-12154 /TestSC/a.asp, line 23
The connection is opened when using Ora oledb con.Open "Provider=OraOLEDB.ORACLE;Data Source=xxxx;User Id=xxxx;Password=xxxx". I am using IIS 6.0 and Oracle 10g.
I wrote a program that connected to a Microsoft Access 2000/2003 mdb file and accesses the data. It works fine, but I'm wondering if there is a way to connect to Access 2007? If I change my connection string, will my program work with access 2007 or is it more complicated then that? And if it will work, can someone provide an example of an Access 2007 database?
View 2 RepliesI am developing an application with Visual Basic 2008 Express Edition and using the Microsoft SQL Server 2008. I have tried to connect the application to the server and database but I couldn't.I have found the following connection string:[code...]
I really do not know where to put this connection string and how to get its details such as SERVER_NAME_OR_IP_ADDR. I am also using SAVE and SEARCH buttons to save the input form to the database search using SQL queries. Do I have to use a separate function for this string or put it every time I need to connect to the database?
I have a standard TCP socket established over WIFI with a peer.During the connection I transfer packets of data both ways.At one point in my program on the PC, the peer receives an errant read event with zero bytes and a 'close connection' command although my PC program has not issued any writes on the stream. It occurs at a similar (although not the same) point in my PC code, usually when I am making a collection, processing data and adding things to the collection. I have checked, and there is definitely no writes occurring from the PC end during this period.There is no problem with the WIFI and anyway, it always happens during the same piece of PC code, therefore it is generated on the PC by my code. I can put a checkpoint in and wait and then run the code, and then the peer will receive the errant transmission at some point during that code execution.
1. Is this normal for socket programming or is this likely to be a bug or an error?
2. Is there anything that can trigger a socket transmission without explicityly coding it?
3. Is there a way of stopping any transmission across the socket whilst not using it? i.e. a temporary hold
I am newbie in Visual studion 2010. May i know how do i setup the connection for a mdb file. Below is my code and i have encountered an error. the error message is "A first chance exception of type '[URL]' occurred in WindowsApplication1.exe".
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i m using Microsoft VS 2008 and in that VB.NET as the language the problem is i m not able to store connection string every time machine changes have to keep on changing the connection string
View 7 RepliesI use the following code in a webservice to fill a SQL 2008 database.
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my project was intially mandated to be done in c#.however a large contributor to the project wrote much of the business logic, which he knows well, in vb.net.How difficult would it be to convert the following c# code into vb.net.
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I am having problem with Visual Studio 2008.... When i add the Microsoft ActiveX Data Objects 2.5 Library from COM References, and just run the blank form, it runs perfectly.... But whenever i declare anything related to ADODB like dim con as new ADODB.Connection, then after that it gives me error and doesnt run the project. A first chance exception of type 'System.IO.FileNotFoundException' occurred in mscorlib.dll. After that if i comment that like (declaration), then error goes........ I tried uninstalling each and every component and VS as well but the error doesnt goes....i am using Windows 7 x64. The same is working in Windows XP x86 in my virtual machine..... as i am not able to start my project
View 2 RepliesI have a problem reading data from an RFID-reader. I connect to the reader by tcp and wait for DataAvailable to be true, then reading the data until I got a end of data character. Then I just go back and waiting for a new DataAvailable. This is done in a own thread for the function.
There seems to be some kind of timeout, If I don't got any data in a couple of minutes, then it just sits there in the do/loop waiting for DataAvailable. I hold the card to the RFID reader, it beeps, but there is no data available. I don't get any exeptions, and the information says that the clientsocket is still connected. Are there anything more I can check?
If I put the card to the reader in a minute-interval it seems as this will never occur. So 2-3 minutes idle:ing seems to do this.
Here are my code to read data from the socket, I have taken away some irrelevant code:
Sub test(ByVal ip As String, ByVal port As Integer)
' this sub is meant to run forever
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I am working on a project. Part of my project requires me to capture data, for example, email address, from certain rows/columns of a datagridview(form2.vb) and displays them in a textbox on another windows form(form1.vb) with a click of a button(Add Contact button). The problem is the datagridview on my form must be able to display databases by making a connection to Microsoft SQL Server 2005 but so far, i have not been able to do that. I have seen many codes with regards to my problem but i do not know how to implement it.
Below are my codes that i have written so far. My program's limitations are not being able to display databases from Microsoft SQL Server 2005 so i created the statement below to add columns and test my codes.
DataGridView1.Columns.Add("CustName", "CustName")
DataGridView1.Columns.Add("Email", "Email")
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