VS 2010 Checking For An Error Before It Happens [TcpListener]
Aug 10, 2011
Basically, 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 am working on a program that gathers test scores from the user in the form of a list box (array preferably). I need to be able to check the user's entries to validate they are between 0-100. I have tried using If statements with a messagebox.show() error message.When the user enters an invalid entry the error messagebox pops up but after selecting ok the program moves on to the next test score.
The GetTestScores procedure gathers the students test scores from the user Sub GetTestScores(ByRef intTestScores() As Integer) Dim intCounter As Integer = 0
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?
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?
I have an object, say Order where if an error occurs, it raises the ErrorOccurred event. If I'm running some code in say, the codebehind for a .aspx page with an public Order registered as WithEvents and I want to check to see if an error has occurred before I run more code, how do I do this? I can't simply check theOrder.ErrorOccurred. Do I have to create a local boolean flag that switches over in the event handler (OnErrorOccurred)?
Example:
Public WithEvents theOrder As New Order Public Sub DoStuff() theOrder.DoSomething() If theOrder.ErrorOccurred Then
it is so difficult to handle and code in vb in grammars and creating rules in visual basic. i need help in order to know what are the basic steps in creating this grammars and rules, in checking syntax errors.
I need to validate that a user doesn't leave the name field blank when they add a record in a datagrid. See code below that I wrote to accomplish this. It works fine if the code is under the 'saveitem' event. However, I want to check it each time a row has been entered (the user may add several records before clicking on the save button). I tried putting it under the 'Row Leave' event but apparently that event "fires" when you click the add button and throws up the error message immediately. I thought about doing it on 'cell' leave but then could not figure out how to determine which cell column you are leaving in order to check the appripriate field.[code]...
Public Function CheckHasRoom(people_id As String, semester As String, year As String) ' Don't let folks already registered for a room register for another. Dim RoomSelected As String
[Code]....
But it is bugging out at hasroom.Any() saying, "Input string was not in a correct format." Any thoughts on why? This is returning a collection of rows just like where I use this same code elsewhere without issue?
I've rearranged the error messages to different spots with no luck. The txt row need to be a number 1 to 10. The txtSeat need to be A,B,C, or D and the txtPassenger shouldn't be left empty.
Public Class Form1 Dim seat(9, 3) As String Dim waitingList(9) As String Dim passengerNames(9, 3) As String
I am currently trying to make an insert statement that will first check for exceptions before it is sent to the SQL server, I am new to this and would like to know what errors I should be looking out for and also what code should I use to ensure the errors will be caught. [code]This is a continuation of a previous thread...it was getting kind of long and the initial issue was resolved so i decided to open a new thread..
I am currently trying to make an insert statement that will first check for exceptions before it is sent to the SQL server, I am new to this and would like to know what errors I should be looking out for and also what code should I use to ensure the error will be caught.
I have the following error for every cell: "the number in this cell is formatted as text or preceded by an apostrophe" To duplicate the error: I have to store this results that come from a Web services as strings array: Sample: (3 by 3 array)
I'm trying to add a string to a listbox if there is none exact string existed inside, but it turns out a very weird error. Look at this. On form_load, I have this: AddHandler Server1.OnUserLoggedIn, AddressOf HandleUser
And then, Public Sub HandleUser(ByVal username As String) 'Here, you handle adding the text to a text box. Me.Invoke(New PrintMessageDelegate(AddressOf AddUser), username) End Sub [Code] .....
The output is when I connect the first client, it works fine. But, when I try to connect the second client, it prints out three times both the listbox1 item and the txtDisplay. It's like get caught in loop, but I have tried other kind of loops like for each and other string comparison too, still work that way.
I'm working on an automated program, and it needs to check the latest email on a certain account (which will be passed to it) every 15 seconds or so. Setting up the timer and the passing to the timer the username and password is easy, but it's the reading the email that I'm having trouble with. How exactly can I read the first few emails from my inbox and put them in an array? And after that, how can I access the body and subject, for example email.body and email.subject?
I�ve written an app that downloads from the internet with my.computer.network.downloadfile mehtod. The problem is it�s supposed to try a numder of urls and if there�s data, it downloads, otherwize the url is wrong. The utl adress is a combination of date and a letter, which the program gets from a database. So for every date, it checks all the letters as suffixes until it finds the right one. However the wrong ones tend to time out or something, which takes forever and also causes some errors. Is there a way to check if a url is valid at all, instead of actually trying a download?
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]
I m selecting the folder & playing all the files in the media player, of that folder. As u know folder contains all types of files including text,zip,image & so on. So I want that when URL that is assigned to Media Player is .txt,then i assign any default image from resources. I do not want to check extensions- Currently I m checking the extension of each file before paying but i dont want dat.
I seem to occasionally find myself trying to compare two List(of T) to see whether or not they contain the same elements. A quick check of the documentation shows the SequenceEquals method, but that appears to check whether the two lists have the same length, and have the same elements in the same order. I don't care about the order. I want to know whether two collections have the same elements. Doing this is not terribly difficult, and seems common enough, so I was expecting that there would be some function that handles it.
I have this line of codes here to check if the records exist.
Try If StudentInfoBindingSource.Find("StudentNumber", StudentNumberTextBox.Text) = -1 Then ToolStripLabel4.Visible = True
[Code].....
This codes works perfectly but there is a problem, if I close that certain form and reopen it and try to input the same student number, the ex.Message for the Try appears and still the progressbar() command executes although the data will not be saved. I want to ged rid of the execution of progressbar() how can I make it work? And as much as possible I want the message box in Else to be executed and not the msgbox in try catch.
I have a checkedlistbox with numbers in it and I'm trying to load a list of numbers from a database and check all of them (they should all be in the checkedlistbox).
I was trying to do this by loading all the values into a separate listbox using my own subroutine (I know that part works) and then finding the corresponding item on the checkedlistbox, like this:
Dim ItemName As String For Each item In ListBox1.Items ItemName = ListBox1.GetItemText(item) If CheckedListBox1.Items.Contains(ItemName) = true Then CheckedListBox1.SetItemChecked(CheckedListBox1.Items.IndexOf(ItemName), True) End If Next End If
But this doesn't work: It never returns a match, even when the item is definitely on the list. How do I make this work?
I'd like to make a small app that checks every few minutes to see if a website has been updated. There is a catch to this, too. At the bottom of the page there is a 'server time' that changes automatically. That server time is located in <pre> tags. Everything else can be checked. How can I do this?
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
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.
