I am an amateur to say the least, but I have made a few basic program. Anyway, I am making a dvd changing robot. The hardware side is already built, and works great with via the serial port. In order to make this thing work I am going to have to make a multi-threaded app, my first.
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I've used mutiple threads in a VB.NET program but I don't know if I did it right.I would like to start about 3 threads.Can they all use the same methods?Will a separate instance of each method automatically be created for each thread?If not, how do you make sure that the data within the method that is used by one thread is not used by another thread?I would like some data to be shared by all threads.How is data shared among threads?What is the protocol for changing the data and checking for changed data?Is there a good tutorial / website that explains how to handle methods and data when using multiple threads?
View 3 RepliesI have a program that are multiple thread. Each thread calculate some data independently. however, they will need share a hashtable which controls a hardware resource. because the resource is limited, so, it may need lock the resource for a thread, and then release it when thread is finished. and the resource can not be reused immediately, will have to wait for some time, say 5 or 10 minutes, for the device to reset.
View 3 RepliesI have been working on a small side project that will read in from a serial port and send off a email depending on what it receives. At the moment I am stuck with a problem of it telling me it cannot access the text box as it was created on another thread. Does anyone know what I can do with this error? I have tried using invoke statements but it does not seam to work. [code]...
View 2 RepliesI just had a new, last-minute idea on to take on a task, so I am running to StackExchange for quick help.
What I want to do is execute a series of methods right in a row, each in their own threads. I want the application to wait until all of these threads are completed, after which the program will resume. It also has to use managed threading (thread pool).
What quick examples could you provide to help me along the way? If it's too complex, what things should I know about so that I can Google it on my own?
I have a main thread which is designed to be a batch processor - it spawns a series of 'child' threads from a loop (which can vary in terms of the no of items) - see below
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However, each of the 'child' threads could take anywhere from milliseconds to about a minute to process - depending on the complexity of each calculation. There may also be a large number of child threads - e.g 100s. Creating large numbers of child threads is not efficient. I therefore want some way to effectively queue each child thread (and cancel if the process is taking too long to complete). Autoevents seems like one way of doing this, but the only examples I can find seem to assume there are two different processes on seperate threads, not one process being repeated.
The program is currently trying to pull information from three different database tables and compiling the information onto one screen, to do this i am using three different connections and a function to handle the data at each stage. The issue is as my code hits PageLoadStage of "2" and runs the QueryDatabase() Function i am encountering an error of: "OleDB exception unhandled: No value given for one or more of the required parameters." This occurs on line 15 of the first code snippet. Can anyone explain this and/or identify any code issues if that is the cause.
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I was looking for some stuff online, and i was looking through my reference sheets for vb.net, but it seems in the code i have found, there is declare in methods. Below is an example i am talking about. The thing is, that i dont recognize it and believe that it is an earlier version of Visual Basic ( 6 or earlier) which used it. Should i just keep looking for different code?
Public Declare Function RegOpenKey Lib "advapi32.dll" Alias "RegOpenKeyA" (ByVal hKey As Long, ByVal _
lpSubKey As String, phkResult As Long) As Long
Goal: Find information on how to implement a method which will check if a certain DSN exists, and then if it does, extract the information and use the information for connection purposes.
I have a text box where i am entering numbers of double datatype andon the Keytdown event of the textbox some checks take pace and in certain circumstances I want to be able to stop the user from entering other information until they enter the right information in the textbox (where it says right here) . now when I say exit sub the textbox somehow loses focus . but this is not how I want it to be I want the textbox to remain with the focus so the user can change the information . How can i go about this. And the other thing is why is my txtDestPayRate1.Focus() just befor the exit sub not working?
Private Sub txtDestPayRate1_KeyDown1(sender As Object, e As System.Windows.Forms.KeyEventArgs) Handles txtDestPayRate1.KeyDown
If e.KeyCode = Keys.Enter Then
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I am designing a backup/restore utility for work.atm i have been able to populate field for PC name, IP address, MAC address, number of printers installed on the PC but i am wondering is it possble to get all the printer information 'with the click of a button' to print all information like the prnmngr.vbs script down.I am able to run a batch file but i wanna get it to go from that app or even embed to batch file to the app and run it form there .
View 4 Repliessimple way to share, only share, in facebook? I see alot of libraries but they come with alot of code and without documentation.
View 2 RepliesHow to start vb.net application from a shared file in LAN I mean that the application is installed in my PC but I want other users to get access to this application using my shared file.
View 8 Repliesi am working on a app. and i need to know how can i share floders that the app will use to save flies over the net. i was thinking about crearting a data base that would save all the files on to it , and then share the data base with fellow co workers, but i do not know how to add a excel file or word doc. in the database. i am pretty new to all of this so any help would be great. the app is writen in visual studio 2010.
basical it will let the user access the file he needs to compelte his work off shore. the files are created and saved as he needs them. once he is finished, i need the app to send the floder to some type of server ( dont have a server yet) so that the office and other co workers can see the files when they run the app.
I've looked in System.IO. but I can't find anywhere to get the unc share name of a path/drive.Anyone know how to get the unc share name of a folder, i.e. 'O:MyFolder'.
View 4 RepliesI have to do an application that share a folder and his sub folder.
This application have to run on Vista computer.
What's the best way for share a folder ?
I am using VB2005 and trying to put an application together.What it needs to do is retrieve information from a binary file, possibly alter that information, and put it back into a new file.The file is a .wav file with data appened to the end. There is an additional section at the end of the .wav file which stores xml data.I have found that if I open this in a hex editor and make a 1:1 swap on any of the bytes that the application that the file is for can still read the XML.If I tried to add or remove characters from the XML then it would not read. I located a header byte and incremented it to resolve this.
This worked as an excellent bandage to do conversions where the data always needed to be changed to the same thing.What I have been asked to do is build logic that allows for different things to happen depending upon what data is contained within the file.The method that I am currently trying to impliment is:
Read through the file with a system.io.binaryreader
Searche for a bytestream that will signal data is coming
For example:
If System.IO.File.Exists("C: est estread.wav") Then
Dim findit() As Integer = New Integer() {&H3C, &H55, &H73, &H72, &H44, &H65, &H66, &H30, &H31, &H30}
Dim i As Integer[code].....
And then extract all the data till the end of element marker "<" It seemed like there should be a better way and I was looking for some insight. If I proceed with this method, I will have to read the file one time to gather the information and then a second time to write it all out with the header modified for length.This is my first experiene with working with binary files in this way.Also,I've been experiementing with building a string and slapping it back in at the end using the binarywriter.write(string) method.I noticed that it was putting in header characters before the string.These seem to change if I change the length of the string.At one point it was d0 07. Later it became e7 07. Does anyone know of a way to prevent this header from being inserted?
I tried a for each loop to grab all of the characters from the string, convert them to a byte array and deposit the byte array into the file, but the header remained the same. When I write the byte array generated from a system.io.binaryreader I do not get this header.
can I have 2 form share the same progress bar? If so how does this work?
View 3 RepliesVisual Studio 2008 / Windows 7 / .net framework 3.5 / Windows forms application
My applicaiton has the following App.Config:
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<configSections>
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I have created a Bus Booking Website [URL]. I want to share the bus booking form with other sites so that they use our services.How can do I this using vb.net?
View 2 RepliesHow can I connect to a network share without using System.Diagnostics.Process.Start?
I need to connect to a network share and get feedback if it already exists.
Can I use some kind of API?
My problem relates to executing an application located on a network share and getting various security exceptions in trying to do so. By far the greatest number of replies to this sort of problem relate to creating a new Code Group under Runtime Security Policy in the .NET Framework (v2 in this case) Configuration tool. However try as I might, and I've spent hours, trying various things with the config tool (and with caspol), I just cannot get my app to work.Still fails on things like reading command-line parameters and displaying a web page in a WebBrowser control or firing up a browser using Process.Start. In fact I've regressed to creating a VB6 version for this particular task as time is off the essence. Which works fine! As I mentioned lots of people have posted on this topic and not s few of them seem not to have resolved their issues either. So I was wondering if anyway had come up with a definitive solution for this problem which, in my case, seems to affect XP machines only? Seems to work OK on Vista, 7, 2003 Server, etc - although I haven't run exhaustive tests in these environments.
View 1 RepliesMy company got a new server, with a new sever share name, etc. I also moved my project from 'My Documents' to the C: Drive. I went through all my code and replaced the old path info to the new path. Tried to publish and received errors stating my temporary key was no longer valid. I googled that error and tried a solution. I created a test certificate and the app published as expected.
View 2 RepliesNow I have finished my another really small program. I have tryed to publish in several ways but with now result. So how can I publish it easily? I will share it so I'd like to have just one "setup" file which creates the another necessary files. (or just one bigger file?) but the main thing is that I dont want to start share 4-5 files...
I get it worked on my computer, that's not a problem. But then I upploaded all of the files (4-5) to mediafire, destroyed program from my computer and downloaded those files: Program didnt worked: Sayd just "U havent downloaded all necessary files" (something like that).
Well I think it's possible also to publish to new wep site. In fact I tryed to make wep site (with www.nettisivu.org ) (finnish quite good wep-page-creater) but the same result: no results at all. If this is the easier way, how I could upload my program straight to that site? In that "wep-page-creator" the final site looks that: xxxxx.nettisivu.org and editing page looks: xxxxx.nettisivu.org/wp-admin/page.php?action=edit..... (xxxxx=my name for site)
I have an app with my own class "something".So, Im going to one of the my modules and declare public var as a class. After fillup this class by date, I would to get this date from the other module of my app. But there this var is unavailavle (its mean I have to redeclare it again. Its mean I'll lost
View 7 RepliesI'm new to VB2008 and SQL Server. I have two forms (frmCustomer and frmDetail). The frmCustomer has a datagridview containing general data of customers, and a button to open frmDetail, which contains each customers detail information. All data modification is done on frmDetail (add, delete, and edit). Currently, both forms are binded to the dataset (same table). When the two forms are loaded, each form performs a FILL function that retrieves the data from SQL Server. In addition, all modifications done on frmDetail does not show up on frmCustomer until I perform the FILL function again on both forms. Seems like I'm maintaining 2 sets of data from the same table, and I think I'm doing more work than I have to. I'm sure there are ways to make this easier, such as bind both forms to a single dataset, so I don't have to do everything twice.
View 1 RepliesIs it possible to share subscripted variables and their data between forms? So far I can't see the variables I made public in one form, in a second form.
View 5 RepliesI'm writing a console app to take care of our automated user creation process which was previously done by a batch file. I need to check if a users network share exist on any of 38 servers but seem to be having trouble finding info on how to do it. From what i can tell i need to use the netapi32.dll and the NetShareCheck function, but i'm not sure how to do it.
this is what i have so far, but it isn't working as it should. it seems to be returning 2311 in almost all cases exept if i use uppercase on the server and device and the device starts with C.
Imports System.Runtime.InteropServices
Public Class NetApiWin32
Declare Unicode Function NetShareCheck Lib "netapi32.dll"
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my old vb6 "WNetAddConnection2 Lib "mpr.dll" no longer work in vb.net 2010. at run time i get "PinvokeStackImbalance was detected".How can connect to network share ?
View 2 RepliesI have a few pdfs I am trying to display in a winform app I am writing.
Is there a way to grab these apps from a share drive on a network, loop through the directory and display them?
I developed a Visual Basic Program in my laptop. I can run the program form my C Drive and works perfectly.
Then I put the program in a Share Drive and:
1. If I run the program from my laptop but in the Share Drive I get this Error[url]...
2. If I run the program from my desktop and the Share Disk it is works perfectly.
3. If I run the program from a different user desktop and the Share Disk I get this error[url]...
I suppose it is a Security Issue or something like that but I am not totally sure and I do not know how to fixe it.