I am using the following code to receive data from a Public Address Controller.the programme sends data...waits for a reply....send more data...waits for a reply..etc.
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is there some way of cancelling the BeginReceive after a delay so that the programme can carry on and inform the user that something is wrong and terminate gracefully?
I'm trying to use a UDPClient object to listen for all connections on a specific port. Devices on my network let me know when there is new data available so I can begin processing the new data, but I need to loop within a thread in order to continually look for new data. This is understandably a resource hog, and it takes up approximately 50% of my CPU load while running.
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The following code waits for data over UDP. I have a test function that sends 1000 packets (datagrams?) of 500 bytes each. Each time I run the test function, the receiver gets only the first few dozen packets but drops the rest. I looked at the incoming network data using Wireshark and I see all 1000 packets are actually received, but just don't make it to may app's code.[code]If I add a small delay after each call to Send, more packets make it through; however since Wireshark says that they were all received anyways, it seems that the problem is in my receive code. I should mention that UdpListen is running on a separate thread.Any idea why I am dropping packets? I also tried UdpClient. BeginReceive/ EndReceive but had the same problem. A second issue that bothers me is the global nature of the receive buffer when using Sockets and I am not sure if I don't process incoming packets quickly enough that the buffer will be overwritten.
Based on the various, somewhat conflicting suggestions from replies to this and other posts, I made some changes to my code. Thanks to all who chimed in various bits; I now get all my packets from dial-up to Fast Ethernet. As you can see, it was my code at fault and not the fact that UDP drops packets (in fact I have not seen more than a tiny percentage of packets being dropped or out of order since my fixes). Differences:
1) Replaced BeginReceive()/EndReceive() with BeginReceiveFrom()/EndReceiveFrom(). By itself this had no notible effect though.
2) Chaining BeginReceiveFrom() calls instead of waiting for the async handle to set. Not sure if any benefit here.
3) Explicitly set the Socket.ReceiveBufferSize to 500000 which is enough for 1 second worth of my data at Fast Ethernet speed. Turns out this is a different buffer than the one passed to BeginReceiveFrom(). This had the biggest benefit.
4) I also modified my send routine to wait a couple of ms after having sent a certain number of bytes to throttle based on expected bandwidth. This had a big benefit for my receiving code even though Wireshark said all my data still made it across even without this delay.
I did NOT end up using a separate processing thread because, as I understand it, each call to BeginReceiveFrom will invoke my callback on a new worker thread. This means that I can have more than one callback running at the same time. It also means that once I call BeginReceiveFrom I have time to do my stuff (as long as I don't take too long and exaust the available worker threads).[code]What is not shown above is the error handling and dealing with UDP data being out of order or missing.I think this handles my issue, but if anybody still sees anything wrong with the above (or something I could do better) I would love to hear about it.
The MSDN Documentation in question can be found here:[URL].. It offers the following code snippet example:
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This is the MSDN example for handling the BeginReceive callback.BeginReceive is called over and over until no more data is available, i.e. EndReceive returns 0. However I am finding that the callback is only fired when there is data available.
I'm guessing that the example is simply wrong or refers to expected behaviour in a previous version of .NET, although it says it is for 3.5.So how do I ensure I have received all of the available data?
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I want to make an application which turns on my computer. A Wake-on-Lan application should do the trick. I allready created something which sends data over UDP, i can see that it sends the data (with wireshark) but it does not send the correct data.
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Say a machine has two seperate IP's. I am running a little test program that connects to an outside piece of hardware that has it's own IP. I receive data from that hardware. I want the same little program assigned to the two seperate IPs on my local machine to get the same data from the hardware. How can this be done?I am receiving data just fine but I am not seeing how to tie the program to a specific IP on the local machine. As soon as I run another instance of my program, not data is received on the second instance.For example: I have a program running on a machine. I want two instances of that program, each on it's own ip
Instance 1: 192.168.1.240
Instance 2: 192.168.1.241
I want both instances to listen for data coming from 192.168.1.50
This is a generic example of what needs to happen. I need to know how to define the local IP's the UDPClient is running on.
Is anyone else having or know of an issue with VB2010 Beta 2 just "hanging" on the install? I can find no documentation anywhere through searches.
View 5 RepliesI have a visual basic program wherein i fetch information from two textboxes format the output of the textbox in the required form and then make the output come as desired I use two arrays to read textbox 1 and 2 separately and then i use for .. next statement to perform the same action for all the lines in the textbox 1 and 2..
Both of them have equal no of lines..I have also give a progress bar in the form and assigned the max value as the number of lines and i have given the incrementation within the program for the progressbar..
When i run the program it runs quite well for certain instant of time and the progress bar also responds according .. After some interval of time the form hangs and the progressbar also hangs at that place..Later after some more time the form is back to normal and the process is in finished form with progressbar at 100%..
Is there any reason why the form hangs..If there was a major problem i must have not got the output at all but i do get the output after certain interval of time..Can this problem be solved??
I made a program that backs up data from the My Documents, Favorites, and Desktop folders on Windows XP to a server. When the data is brought down from the server, it brings it down in Windows 7 format. So, for example, the directory to My Documents in Windows XP is "C:Documents and SettingsusernameMy Documents." The same directory in Windows 7 is "C:UsersusernameDocuments."Everything works fine in terms of putting files and folders in the correct directory, but when bringing the data down from the server, the program sometimes freezes up and doesn't ever seem to get out of that state. It also makes the computer very slow and unresponsive after a while. Does anyone have any idea why this would occur?
Below, I have a code snippet of my copying code. I include a sleep command and a DoEvents command to halt the thread for a very short duration of time in order to make the UI more responsive.[code] I believe I may have to use some multi-threading to get this to work properly, but I've looked it up and cannot find out how to implement it in my program.
I have a datagrid which receives updates for every 1 minute from the database. Whenever it gets update my whole form gets freeze and I cant do anything. To add on when first I log in also the log in page gets freeze because the form is being loaded during the first time.
View 1 RepliesHere is vb.net 2008 code is: Public Function CheckURL(ByVal URL As String) As Boolean
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when a url is processing in checking it hangs my application for a while. Is this possible it checks smoothly all url list without hanging my application.. Is there any other fastest way to check urls? Note: I have about 800 urls in file to check all links a valid by website responce or not.
Creating an application that uses both namedpipes and TCPIP connectivity to pass data between 2 legacy applications.
When there is actual data to pass everything works great. But when the application is looking to see if there is any data to read from the named pipe side and there is no data, the Peek hangs until there is data. Is there a problem in the way I have it coded or is there a timeout that needs to be set?
Code:
'
' declarations
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Private in_pipeName As String
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I would like to place a brush under the cursor as I move the mouse around a picturebox, so the person can see what they lay down when clicking. How could I do this. I am working on a custom scribble application.
View 1 RepliesI have a windows forms app (32 bit) written in VB2010 which occassionally hangs in windows when minimised to the task bar You click on the icon on the taskbar and it will not come back up on the screen
No other modal forms are open in the application when the hang occurs Other programs respond OK
I ran Process Explorer against when it was Hung but do not know how to interpret the stack page, or even if it is helpful STack page with my application selected and Threads tab selected with CSwitch Delta column sorted descending. Then double clicking the top entry (my application .exe)
Note: This is running on an x64 machine, but also hangs on x32 machines
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software developed in vb.net(communicating with serialport) hanging and it is giving these rexceptions 1.The device does not recognize the command2.Unhandled exception has occurred in your application. If you click continue, the application will ignore this error and attemptto continue. if you click Quit, the application will close immediatly
View 1 RepliesI'm not sure how to explain what's happening but it seems to be deadlock, i did search along the forum and actualy did find who had the same problem as i did. Unfortunatly i'm too new to this Threading and could not understand why does this deadlocks happen or how to avoid them.I'm using the following
Dim t As New Threading.Thread(AddressOf MyTestingSub)
t.Priority = Threading.ThreadPriority.BelowNormal
t.IsBackground = True
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I am new to the forum. This looks like a cool site! I have a bit of experience in VB .Net, but not with threads or backgroundworker processes. I am sorry that the description is so long, I tried to make it as short as I can, but it is rather complicated. Here goes:
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Edit 1: Uninstalled & Reinstalled Edit 2: Same problem. Seriously? Yes.I am having a problem with msvb7.dll eating 50%+ cpu on my dual core system. This usually lasts 10-30 seconds or so, during which time the IDE is non-responsive.
This occurs when I do pretty much anything in the text editor, and can be replicated by simply adding blank lines to a function, and then deleting them. Or pasting some code. Or... lotsa stuff.
SP1 installed I had DevExpress' refactor/coderush, components, and codeit.right installed, but have removed all 3 of them. (I had installed the latest version of Refactor Pro! (9.3.4), perhaps the day before)
I have tried a VS.NET Repair. There is a kb that referenced some cpu destroying with vb, but it was included in SP1
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I have a really simple form with a button that fires a Sub I created which gathers data from ActiveDirectory and adds it to an Excel Sheet. The problem is, when I click this button the whole form hangs. So I figured the operation that gathers the data and adding it to the Excel sheet should be run in it's own thread, so that the form won't hang. Possibly it would be great to add a progressbar as well. The progressbar however is located at the Main userform that starts up once the projects is run.
I've got one MainForm.vb and one CodeFile.vb. I want most of the code in the CodeFile.vb so it's tidier.
MainForm.vb
Imports User_edit.CodeFile
Imports System.ComponentModel
Public Class MainForm
Private Sub btnImportData_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnImportData.Click
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Notice the ExportFromAD Sub I've got in the CodeFile.vb. This is what is actually doing the work. In the For each loop that adds data to the Excel is where I've put the MainForm.MyBackgroundWorker.ReportProgress(i * 10). Problem is, it doesn't actually update the label on the form. Which I find pretty weird because the form isn't really hanging or anything. Is it trying to access a different thread or something? Meaning, the form is run on it's own thread which can't be accessed from my second thread?
Yesterday I worked on an MVC 3 project in Visual Studio 2010 and then shut down Visual Studio before leaving work.This morning when I try to load the same project in Visual Studio the project hangs. I have restarted my computer, disabled all add-ons and extensions that I could. Still no banana.I would try to clean the solution if I could get it to load but I can't.
View 2 RepliesSetting a hanging indent using full word automation. I am using word 2003 and vb 2005. I am inserting paragraphs in the document and I am having some difficulty getting the whole paragraph to indent.
View 8 RepliesI have a vb.net 2010 windows forms application (32 bit) which is hanging regularly on SOME computers, mainly when minimised to the task bar
View 6 RepliesIs it possible to wait/suspend execution for a certain amout of time without hanging the main UI thread?
View 7 RepliesI am trying to write code for a login to my program. But the code I have written freeze's the screen. Basicaly I want to check if username (TextBox1) has text in it and then check if password (Textbox2) has text in it. if either textbox has no text then a MsgBox show's with an OK Button. and then I dont want the program to run. I want The login form to reload so the user can insert thier username & password. the code I have is below.
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The following code works fine but seems to leave instances of excel.exe running in the background. How do I go about closing out this sub properly?
Private Sub ReadExcel(ByVal childform As Fone_Builder_Delux.frmData, ByVal FileName As String)
' In progress
childform.sampleloaded = False
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I'm doing a big loop in my program and throughout the loop I'm updating the textbox in the form.
However the form "hangs" untill the loop is done. How can I keep the form visible and be able to read the updated textbox while the loop is still running? I tried Me.Update() but it didn't work. I'm sure there was something like processdata or something like that but I can't find it anymore...
Example
For x = 1 To 10000
form1.textbox.text=x
Me.Update()
Next
I'm administering an application written in vb.net 2005 and running on windows XP but displayed to the client through citrix. The client has recieved a big red x over on of the tabs. I am unable to duplicate it?
View 5 Repliesi was trying to get a ftp client work on vb.net but i recieved a error 530 not logged in.
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i want some method for get sent and received speed of internet?
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