Client/server - Can't Access Communication Variable?
Aug 14, 2011
I have a client/server program. There is a variable called readData that takes returndata and places it there. My question is, why can't I access this variable directly, for instance, varC = readData and then try to access a piece of it i.e. textbox1.text = varC(2), I get an error "object reference not set to instance of an object". Why is this happening? It is because the readData is a networking 'component'? How do I get around this? I can post more code from the server app if needed.
[Code]...
View 16 Replies
ADVERTISEMENT
Jul 23, 2008
The problem I have is: When I click on cmdListen in the server form and cmdConnect in the client form,both programs won't respond and they crash for some reason I don't know.
Client source code:
Code:
Imports System.Net.Sockets
Imports System.Text
Public Class Form1
[CODE]...
Code:
Imports System.Net.Sockets
Imports System.Text
Public Class Form1
[CODE]...
View 3 Replies
Jul 7, 2011
I made some code in vb.net which checks if a certain process is running, and returns a 1 if it is, or a 0 if it isn't. Now I want it to send a packet to my server or something which would log the IP of the client, or something similar.
View 1 Replies
Jan 17, 2012
Im doing a little program (.net2) that need to get info from a server.For starters I just want the Client-program to send a "Hi" and receive a"Ok" from server when client-program is started.
View 4 Replies
May 12, 2011
I'm doing a small project. It works on a LAN. The working of the project is:In client side, a user would enters "username" and "password". It would sent that to the server, along with the time.The server would authenticates info on checking a db and writes some info to the db.Also, the server should be able to sent some commands or instructions to the clients.These commands on received by the client, it would invoke certain functions/subs on the client based on the command.So, would it be better to use TCP client & listener or WCF ?
View 6 Replies
Oct 4, 2011
The client/server communication will only take place in the same network.I can use TCP, but then I have to configure separate IP ports for every server instance. I can however simply use named pipes so I don't have to think about port numbers and simply use the name of the server instance.There will not be very frequent and/or large data client/server communication. It's some sort of a ERP application that will only communicate once per 30 seconds on average.
View 2 Replies
Jun 3, 2010
How would I make a Visual Basic application talk to a web server? Someone will press something on the site and I want the application to display the information that the web site passes along to it.
View 2 Replies
Nov 5, 2011
I have a TCP connection code for client and server communication. It's not meant to be malware but it collects the clients computer information and then connects to the server.
It successfully "connects" but then immediately disconnects.Here is the code for the server:
Dim Listener As TcpListener
Dim Client As TcpClient
Dim ClientList As New List(Of ChatClient)
Dim sReader As StreamReader
[Code]...
I have port forwarding all done and it works if I run the client and server on my own machine. If I run the client on another machine though It gives me a message box saying that it connected with the clients remote IP and at the same time it tells me it disconnected. The client never sends the system information. What is the problem?
View 2 Replies
Oct 13, 2010
I'm not sure what I have done wrong, I am trying to get my program to send data (UsernamesPasswords) from client to server, then the server says if it's right or wrong.
The error is on this line:
Dim networkStream As NetworkStream = TcpClient.GetStream()
Heres the Client:
Private Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
If TextBox1.Text = "" Then
MsgBox("You must enter UN/PW!")
[Code] .....
View 4 Replies
Dec 29, 2011
Code of my web page.I made changes according to ur suggestions but title is invisible or not displaying what has missed by me [code]...
View 1 Replies
May 9, 2009
how to create a client/server... But I couldn't... I don't want anything fancy. Just want the client to send the server 4 numbers, depending on the user's choice; after that, the server would turn off the pc, restart it, etc. It all depends on the number received. Is there a rather "simple" way to do it? If it's not to much trouble you could use Atheist's example. (Btw I don't understand the code and, yes, I've checked on [URL])
View 9 Replies
Jun 27, 2011
Hey guys, I am trying to send data from client to server (encrypted) and the string sent from the client is not the same as recieved from the server. I've been killing my brain for hours to get this to work but I cant manage. Im converting everything to Base64 string.
Client:
Public Sub SendMessage(ByVal msg As String)
Try
SyncLock myclient.GetStream
sw = New IO.StreamWriter(myclient.GetStream)
[code]....
View 4 Replies
Sep 15, 2011
I would like to ask some advise for the best thing to do regarding with this matter. Im working with a client-server application and I should run a pdf file from the server in the client application. The file name is the only saved in the database(MySql) and the full path is in the server. What technique should i used i order to access this file in the server., I planned to use the winsock. Im working in vb.net.
View 1 Replies
Dec 10, 2011
I would like to create a server program that accesses an "ms access" database. I will also need a client program that connects to the server. The reason for this is that the server is a mediator for several clients. Since I am using access, I plan on maybe having 20 or 30 clients connect to the server only. The client will have access to a virtual market. So when a person buys or sells something on the market, the server mediates the transaction and etc. At the same time, the access database saves each clients data as well as the overall market data.
View 1 Replies
Jun 21, 2010
We are creating a Who wants to be a millionaire style game in VB. Our server is pulling information such as questions and answers from a Access Database and sending them to the contestants (Clients). All transfer of information is directly from the server to each client. One of the "Life Lines" we want to use is "Ask a friend", where one client is able to Instant message another client for a short time to get help on the question.
[Code]...
View 2 Replies
Oct 29, 2009
I've been playing around with the TCP client/server sample code I found on [URL] but I can't seem to get it to function correctly. The problem I am having is that if I try to send data from the client a second time I get nothing back, not even an error that it couldn't send data. Every time I run the project it works the first time but that's it. When I was running the code line by line it seems to get to 'networkStream.Read(bytes, 0, CInt(tcpClient.ReceiveBufferSize))' and then it jumps over the rest of the routine.
[Code]...
View 3 Replies
Nov 15, 2011
basically i just want client to say "C: emp" ENTER
then, server must reply with all its files in c: emp
View 1 Replies
Mar 30, 2009
I've basically made a basic tcp server/client application. The thing is that I'm behind a router and so will be the other people that use my clients. I've had to use port-forwarding or the software "rinetd"to run quite a few applications online.
Let me explain: I'm on a lan network that connects to the internet. Whenever I want to host a server - for instance a basic ftp or http server. If I give my external IP to anyone, they won't be able to access my server. Even if I portforward, it doesnt work. I have to use rinetd here. For other applications, portforwarding works. I'm not sure how these things work at all.
Anyway, my issue now is that I have created this server/client application. I'm having serious doubts that if I run the server, I'll have to either a) portforward or use rinetd to get people to connect to my server. IF I need to portforward, that's fine. However, using rinetd would really suck... My 2nd concern is as follows: IF the person running the client is in a similar situation as me (i.e he's on a lan that has a router which connects to the net), will he have to portforward or use rinetd as well? If he portforwards that's fine. But I don't think I could get people to use rinetd.... Also, if there are more than 1 person on a lan trying to connect to my server, there is a big problem when they try to portforward: they will only be able to allocate one of their internal ip to that port, and the others won't be able to connect, right? How does this work? I mean, I use many softwares like msn/skype/(some games)/firefox that do not need portforwarding/rinetd. Yet they work. My housemates(other people on the lan) use the same softwares, and it works fine. There's no clash/probs watsoever How come these run fine?
Anyway, back to my issues. Given I have no knowledge about how the above work, I was wondering whether there was a way to host a vb .net server application on an external website (external to my house) so that I might *avoid* the above mentioned problems, and to what extent that would be a sound solution.
View 11 Replies
Dec 1, 2008
I have been reading through Atheists posts in regards to client-server and TCP client/server connection's. But how do i go about writing a program with 1 client and server where the client side creates a text file.Once the server sees there is a text file it connects and downloads it to itself or the client pushes the text file to the server.Once on the server i will read the text file and put its info into a sql db.
View 14 Replies
Aug 18, 2009
Im using the code from [URL] as a starter, most of the code is the same. the chat system works fine but on the client a added a disconnect button "clientSocket.Close()" and as soon as i click that i get errors, on the client, this is the code...
Private Sub getMessage()
For infiniteCounter = 1 To 2
[CODE]...
And this line...
serverStream.Read(inStream, 0, buffSize)
gives me "Unable to read data from the transport connection: A blocking operation was interrupted by a call to WSACancelBlockingCall."
Now im talking the server, after the client clicks disconnect or closes by task manager, looses connection, etc the server crashes and gives me.
View 5 Replies
Jan 25, 2010
There is some one who know how to do a connection to the server with using vb.net?
View 1 Replies
Dec 9, 2010
I develop an application using vb.net.application will run on client server architecture.when we try to execute the program in client side then it will give me an error which is related to sqlclientexception.how can i handle this situation.i used vb.net 3.5 as front end and sql server 2000 as back end.i have done total coding with system.data.sqlclient namespace.
View 6 Replies
Apr 19, 2012
Chat Client to Client Without Server Just Use IP Address For it?
View 1 Replies
Jul 27, 2011
I need to valid the user credentials connecting to server using TCP communication. How to conver the following code compatible to VB.NET 2003.[code]
View 2 Replies
Aug 10, 2009
Multi-User Chat Program (Server & Client) with Main Server?
View 1 Replies
May 13, 2011
i have 2 application clinet/server the server broadcast media files to client i used tcp/ip protocol the server code is work good but i have a problem in client code i need ineed someone to correct the code .iwll show where the error is in the code note: i call the class in the main form dim a as recive in the starter of the main form class to be gloable .
[Code]...
View 4 Replies
Apr 6, 2012
Case : I'm creating an application (desktop application) with VB.NET (actually windows form), and using SQL Server Express 2008 for its database.
[Code]...
View 1 Replies
Nov 28, 2009
This emailing code wont seem to work in my program. I get an exception "The SMTP server requires a secure connection or the client was not authenticated. The server response was 5.5.1 authentication required."
Imports System.Net.Mail
Public Class emailStudent
Private Sub sendEmailButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles sendEmailButton.Click
SendMail()
[code]....
View 12 Replies
Jul 9, 2009
I wrote a VB code to call a sp in sql server 2005, which returns a recordset as follows:Dim objRecordset As ADODB.Recordset Set objComm = New ADODB.Command
Set objRecordset = objComm.Execute If Not objRecordset.BOF And Not objRecordset.EOF Then
Set objRecordset = objRecordset.NextRecordset I need to continue to get next recordset since there are many select statements inside the sp which I need to get the data. The code works fine when I create the DSN using SQL Server but it does not work when using the connection string or SQL Server Native Client DSN. It either breaks at Set objRecordset = objComm.Execute ( connection string )or at If Not objRecordset.BOF And Not objRecordset.EOF Then(SQL native client )
I have worked on this for a couple of days now and could not figure it out.Is this a bug in SQL Native Client or something related to some configuration on the database side? IS there a way I can change the connection property to get this working using SQL native client or connection string?
View 1 Replies
Oct 26, 2011
I made a simple TCP server (I've found the example on the web) in VB to receive data from about 40 TCP clients.The clients are not synchronized but sends data about every 18 minutes; the problem is sometimes several clients sends data at the same moment, so I can't receive data.I also made a second program that reads the data (server program writes data on a file, read from the second program) scheduled.
My question is this: I've seen on the web examples about Multithreaded Server Socket Program, so I suppose this could manage my 40 clients (but now the clients are syncronized and send data at the same time in client mode) or is better get data (I have a central client that asks data to all 40 devices in server mode)?
Second question: can I make a single program where I run both TCP client and TCP server at the same time?
View 1 Replies
