I've put together a multicast client/server application in VB.Net using VS 2008. I can run the server on either Windows XP or Windows 7 just fine. The client runs fine on Windows 7, but throws an exception on the line that adds membership to the multicast group (line number 9, including the subroutine definition). [code]
View 2 RepliesUDP multicast client and server chat application.
View 10 Repliesfrom the documentation we have this: Multicast Delegate: Represents a multicast delegate; that is, a delegate that can have more than one element in its invocation list.
so am i right to say that Multicast delegate is no different from a normal delegate other than the fact that it has arguments. so System.Action is a 'normal' delegate whereas System.Action(T)(Byval obj as T) is a multicast delegate?
I'm using a TcpClient to try and connect to a server. I have the following code, which uses valid IP addresses and ports:[code...]
My problem is that the server I'm using is my own, and when I intentionally don't have it running, an exception occurs whenever I try to access any of TCP_SENDER's properties (in the example above,
the "SendTimeout" property throws the exception, but any other property has the same behavior). The exception thrown is "No connection could be made because the target machine actively refused it.
This exception is expected since I don't have the server running (and sometimes in real-world scenarios I won't), but the real issue is that the "Try/Catch" block I have won't catch the exception.
If I run the code above when the server is down, the "Catch ex as Exception" code is never reached; instead the program just throws the above-mentioned exception with its green font at the "Why can't
I catch the exception? Even if I give trash inputs to the system I should still be able to handle any exceptions that might occur, right?
I am working on some window application and facing the following error while running my code An unhandled exception of type 'Oracle.DataAccess.Client.OracleException' occurred in oracle.dataaccess.dll
Additional information: System error. I don't know what type of error this is. I have successfully added the reference dll file
I want to build an application which will multicasting over the internet. I already have same solution for the LAN environment (UDP).
View 1 RepliesI want to make a basic winsock chat server and client, and I just need to know the basics, like.How do you determine where to send the data?How do you determine where to receive data from?How to actually send and receive the data?I just don't want to read from a website that has a lot of extra information. I just want to start off with the basics so I can actually learn.
View 2 RepliesI have some experience creating programs that use tcp to transport information from a server computer to a client computer and vise versa. However, I am unable to create udp server/client programs with visual basic.net . My goal is to be able to set up a connection with several computers that can communicate with eachother.Kevin Schaefer "The world is round and the place which may seem like the end may also be the beginning"
View 1 RepliesI am trying to use MessageQueues to notify users of an application of data changes using the Multicast feature, but can't get it to work : the workstation that sends the message does receive it, but none of the other running workstations seem to catch the sent message.Sending messages is done as follows :
Dim sendQueue As New Messaging.MessageQueue("FormatName:MULTICAST=234.1.1.1:8001")
Dim message As New Messaging.Message("message body...")
sendQueue.Send(message)
And receiving them :
Dim receiveQueue As New Messaging.MessageQueue(".private$myQ")
receiveQueue.MulticastAddress = "234.1.1.1:8001"
receiveQueue.BeginReceive()
[code]....
So I'm obviously missing something, and I can't seem to find any good ressources on multicasting with MSMQ 3.0 in .NET.Also, what is not clear is wether I should use a local queue per workstation, or one single remote queue on a server to multicast messages ? And does using the receive method on multicast messages purge them from the queue ?On a side note, all workstations are on the same subnet, and all have MSMQ 3.0 installed.
Despite what the Queue properties dialog says, permissions are NOT totally ignored on unauthenticated queues, at least when using multicasting. If you want your queue to receive multicast messages, it must give to 'ANONYMOUS_LOGON' the right to 'Send messages'. Otherwise, multicast messages are just discarded without any notice in event logs or whatsoever (unless I missed something).
On Win7 stations (XP stations seem to do fine, which is what pointed me to the actual problem), queues created through code do not have such permissions, and hence must be manually set after creating the queue :
Dim msgQ = Messaging.MessageQueue.Create(queueName)
msgQ.SetPermissions("ANONYMOUS LOGON",
Messaging.MessageQueueAccessRights.WriteMessage)
It would seem that internally, MSMQ uses that account to write multicast messages to unauthenticated queues.
I 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
[code]....
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.
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]...
It is possible to catch an exception and throw a new exception which wraps the first exception as an inner exception: [URL] Also, if I call a function and it throws a certain error, but I catch it, will the calling code's catch handler execute? If so, and it is of a higher exception type, is this not wrapping the exception? eg I can throw exception ex of type IndexOutOfRange, log it but rethrow, catch a higher up exception and do something, or I can throw a new exception and wrap an inner exception like:
View 1 RepliesI 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 RepliesI have an application that takes a series of reports and sends them as attachments in an email to a specified group of email accounts.
When I run the Java version of this using apache commons and the same setting, the email is sent. However, when I run the VB.NET version of the code, it fails on my local machine and on the client machine.
I have a VB.NET web application running on a server that uses similar code. I tried that code locally and it fails. Yet, the web application is working perfectly.
Why is it that the Java application can send the email, but the .NET application cannot?[code]....
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.
Chat Client to Client Without Server Just Use IP Address For it?
View 1 Repliesfor a school project i need to make a vb application that can stream from client to client.
View 4 RepliesI have a large project where we have 2-3 dll projects that are converted from VB6 to VB.NET. We have fixed all the issues that caused compilation errors, and most of obvious issues in running, so now we have basically a program up and running. The exe is created from scratch in VB.NET, using a lot of functionality from the converted dll's (including GUI forms). What I wonder is when I run the program in debug mode, I get a bunch of warnings in the "Immediate Window" saying:
A first chance exception of type 'System.Exception' occurred in Microsoft.VisualBasic.dll
...and some of other type (but most of them in Microsoft.VisualBasic.dll).I was wondering if this is common in projects converted from VB6, or if it is caused by bad design in our code...
When I try to create a instance of a COM class it throws an exception as Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG))
View 2 RepliesWhen I try to create a instance of a COM class it throws an exception as Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG))
View 4 RepliesBelow is my code, but when i send the message thru client socket i receive Specified argument was out of the range of valid values. Parameter name: size
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim serverStream As NetworkStream = clientSocket.GetStream()
Dim outStream As Byte() = _
System.Text.Encoding.ASCII.GetBytes("0800822000000000000004000000000000000920092126012345001")
[CODE]...
this is probably easier than I think it is.I would like a client-to-client messenging system without using Winsock if possible. At the moment an IP based connection system would be okay.
View 8 RepliesCan't find any free ones so thought I would work on one on my own for the heck of the learning experience with TCP stuff.I'm about ready to start on the messaging aspect of it.The biggest thing I'm wondering about is figuring out when people are online.I'm not too sure how the whole thing works.Say I turn on my messenger. Would my messenger just send a message to all IPs on a certain port to say I'm online and then wait for a message back from the IPs that can return messages and then figure out who is online that way?
View 13 RepliesI'm trying to catch a user defined permission exception - i.e. a user does something their level of system access won't allow, permission exception is thrown. My problem is, the exception is caught and then rethrown as a genertic System.Exception.Is there any way I can deduce the original exception type, without resorting to string comparisons, like if ex.ToString.Contains("Permission denied"
View 2 RepliesWhen catching an exception in .net, you can have as many type-specific exception blocks as needed. But I usually try to have at least one "general" exception catch block. But is there a way to get the type of the "real" exception thrown that is caught by the generic exception handler, perhaps using reflection?For example, if I have
Catch ex As System.ServiceModel.FaultException(Of InvalidUser)
ProcessModuleLoadException(Me, ex)
Catch ex As System.ServiceModel.FaultException(Of SQLExceptions)
[code].....
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 RepliesHey 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]....
i have about 20 possible exception messages that i want thrown when an error occurs.i need somthng like this when catching the exception
Try
' do domthing
Catch ex As CustomInvalidArgumentException
'do domthing
[code]....
do i have to create a class that inherits from Exception for each type of exception?
I have the following code :
Imports System.Data.OleDb
Private Sub getData()
Dim connStr As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:
[Code].....
Exception Text : Can-not find installable ISAM.
Is there anyway to create a Custom Exception without inheriting System.Exception?
my reason is that they have a lot of methods which i do not wish my Class to have.