Multithreading - Limit Time An Operation Can Take
Dec 18, 2011
How can I limit the length of time an operation is allowed to take?
I have an external library that processes image files. I'm running it against thousands of images, and every now and then the library gets stuck on certain images. If I need to skip an image here or there, no problem, but I can't have the process get locked up, so I want to impose a maximum amount of time that the process is allowed to take for each image before I force it to give up and move on to the next image.
View 1 Replies
ADVERTISEMENT
Aug 13, 2011
I'm having difficulty in working with MultiThreading.I want to add to my project a ProgressBar to show the working flow.I'm getting combinations from many Strings, the number of combination can be really big, so it takes few seconds or minutes.
View 6 Replies
Oct 30, 2011
The error occurs at: For i As Integer = 0 To txt_load.Lines.Count - 1..The project exists of 2 rtb's. One with a list of lines. The other will be filled with the converted lines. The main reason that I use it is that I want to use the app during the conversion. The second is that I want to learn how this works.[code]
View 9 Replies
Apr 15, 2010
I realize this has been covered a million times before but with threading sometimes a problem is app specific. I have a multithreaded app that assigns a url to a thread which it then fetches and crawls. Now the function where I collect each threads items I have added synclocks assuming this would avoid alterations. But I get the "collection was modified, enumeration operation may not execute" error. look at my code:
For Each landingPage As String In landingPages
'logger.constructLog("Working on landingPage link: " & landingPage & " at " & DateTime.Now.ToString, True)
[Code]....
View 2 Replies
Mar 19, 2010
I have this script:[code...]
View 1 Replies
Dec 16, 2009
I want to quickly limit the time that someone can use my program and do it without licensing software for now. Can I use an If'Then statement to check to see if today's date is later that a date that Ihard type similar to this conceptually. I am using VB2008.
If today's date > 1-1-10 then
Messagebox.Show ("Your trial period has expired.")
Else Form2.show()
View 4 Replies
Sep 19, 2010
I have developed a utility which I would like to make available for demo purposes. I would like to allow people use it for full 30 days and stop. Does Visual studio ships any tool to do this? if not can you please point me to a way or piece of code to do this.
View 3 Replies
Nov 10, 2009
I want to set a time limit over openFileDialog window, if, for example, 10 seconds elapsed without any user input, it will be killed automatically, how to implement that.
View 11 Replies
Apr 12, 2012
I have a process that recieves a request and issues a response. Sometimes createing the response is taking too long. I would like to start the request, and after 8 seconds, if the response has been created, I would abort the process and send back a generic message.
View 3 Replies
Jul 25, 2011
i've the need to upload two files in the same time, with the same functions with the component backgroundWorker in multithreading.
That is, i'll use a function to launch the upload fase of two files in the same time, trought the backgroundWorket component.
My question is: how can i differentiate the manage of the two upload fases in the
backgroundWorker DoWork process?
View 4 Replies
Feb 12, 2010
How i can prevent the operation of more than one copy of the program at the same time.
View 9 Replies
Dec 28, 2010
I need to know the time elapsed during this copy paste operation and then show it to the user
[Code]...
View 11 Replies
Jan 18, 2012
i have a program im working on that has 68 different buttons on 1 form. each button opens a seperate form. each from opened from the buttons starts with "helmet_" i need a way to only allow one form with that starting name to be open at a time. otherwise you could open all 68 forms at once and that would cause issues.
View 9 Replies
Jan 4, 2012
I'm trying to convert code from Delphi to .Net. I'm stuck on one line:
//Delphi code ss := Copy(ss, Length(ss), 1) + Copy(ss, 1,Length(ss) - 1); 'vb.net code ss = ss.Substring(0, ss.Length - 1) + ss.Substring(1, ss.Length - 1)
Delphi combines the two substrings, while .Net just concatenate them like a copy.
View 2 Replies
Nov 13, 2009
I have a dictionary object (let's call it _do) I am using to cache some values for use in a multi-threaded program. I have a single controlling parent thread, with a timer function _doTimer() which can kick off child threads with a new instance of class MyThreadObject in each. My parent thread has _do as a property and with each time _doTimer() gets called, it may or may not repopulate _do depending on cacheflag settings. I pass a reference to _do to each instance of MyThreadObject and those threads at some point read the values of _do but DO NOT write to it.
What I want is to ensure that the child threads do not try and read _do whilst the parent thread is writing to it. Same thing but very slightly different -> I also don't want the parent thread to write to _do whilst the child threads are reading from it. However there is no problem with 1 child thread reading the values of _do at the same time as another child thread is reading the values - so ideally I do not want each child thread to completely lock out read access, only locking out Write access.. The code is roughly like this:
[Code]....
View 3 Replies
Sep 6, 2009
I have an ASP.NET application with a SQL Server back end. I am storing all my dates in UTC format and doing the appropriate conversions to the local time zone of the browser viewing it. One of the pages asks for a start date and end date (no times).
I am taking the start date and setting the time to 00:00:00 hours (midnight) and I'm taking the End time and adding a time of 23:59:59, so that the date range covers the whole day. Now what I'm trying to do is do a SQL query to do a search for records in this date range. The problem is, the data in SQL is in UTC time and the user is typing their dates and times in their local date and times. My quickest solution was to convert the date and time to UTC, then search the records. However, by doing this, I am to believe ASP.NET converts the given time and date to UTC based on the server time zone. How can I convert a date and time to UTC time based on the time zone of the user?
View 5 Replies
Jan 18, 2010
What is multithreading and how do i do it in vb.net?
View 2 Replies
Dec 17, 2011
I am using an Application server for calling Oracle Reports and I have a URL to call the report. When the report is called the server converts it into PDF but when report contains large data it takes a lot of time to load. I want to do in asp.net that when I call the report url it opens the PDF file and copies it into the root of my web folder. The next time when I call the URL it opens the PDF file and creates a new PDF on backend for next call. I have made this function to download file
[Code]....
View 2 Replies
Mar 28, 2009
In which situations we can do the multithreading and deadlock concepts. can give some examples
View 4 Replies
Feb 27, 2011
Basically I am making a proxy testing program. A user can supply a list of proxies to test. What i want to be able to do is have them be able to specify how many threads they want to run. Then have the program go through the list testing each one using the amount of threads supplied. Really not sure even where to start on this. Threadpooling?
View 3 Replies
Dec 21, 2011
What does common data or data that's in a common, look and is treated by multithreading? I'm quite aware that acess to such data would have to be synchronized, but beyond that is it acessible?
"MODERN PROGRAMMING is deficient in elementary ways BECAUSE of problems INTRODUCED by MODERN PROGRAMMING." Me
View 15 Replies
Apr 13, 2009
I have a class with a background worker in it that does some tasks on a separate thread. I want to fire some events from the background worker thread to the 'main thread' of the class, so that when using this class your not obliged to go make invoke calls for every event handler your using.I'm at a loss of how to do this though. When having a similar problem in a form of usercontrol I always use Me.Invoke, but this method is not present in a class inheriting system.object.
View 1 Replies
Mar 1, 2011
I have a screen that checks for alerts every 30 seconds by looking up outstanding issues from a database.When there is an alert, an audio file is played depending on the alert.It takes 1-2 seconds to grab this audio file which caused an issue with global screen freezing, so I added multithreading where it plays the sound file. This seemed to work fine.However I am new to multithreading and am not sure if I'm working with it efficiently..I have simply declared the sound-playing function as a thread at the top:[code]I am unsure if starting and aborting the thread is the right way to do it. However if I suspend or make the thread sleep I would have to determine whether it has been run before.
View 18 Replies
Aug 22, 2010
I have read many articles on multithreading over the past few days and so far I'm fairly comfortable with how it works. I am now working on my actual application, and have come across a few design issues that I'm hoping somebody has experience with.The basic premise of the application is simple. A database filled with files names and a "converted" field that has a 1 or a 2 in it (1 for unconverted, 2 for converted). The application loops through every record where "converted" = 1, retrieve the file and convert it.
My single threaded application works fine, except its far too slow. Due to the huge amount of rows in the database (4 million+) and the time constraints on the project, I have decided to run as many threads as the hardware can allow to cut down on the timings.So, the dilemma is accessing database records and which threads should grab which record and how.
View 3 Replies
Nov 23, 2011
I have a function in my program that adjust sales for multiple days. Sometimes it needs to adjust up to 3 months and the tasks takes a while so I decided to split up the work between multiple threads. The way I have it working is say I need to adjust 3 months. I have the first thread adjust sales for the 1st month, the second thread adjust sales for the 2nd month and finally a third thread that will adjust sales for the 3rd month. Since all three threads are performing the same tasks except for different date range they use the same procedures. Within those procedures I make a call to the database to extract the sales for the given month. At some point it seems like the threads start to use the same SQL Data Objects because I am receiving the below error."There is already an open DataReader associated with this Command which must be closed first."Below is the first procedure that is ran by each thread up to the line where it errors out.
Private Sub Process_Adjustments(ByRef objAdjustBillCodeThreadParameters As clsAdjustBillCodeThreadParameters)
Dim cmd As SqlClient.SqlCommand
[code]....
So all three threads call this subroutine and the first thread does the data fill with no issues and then sometimes even the second thread does the data fill with no issue but then the third thread crashes and produces the above error. It seems as though the threads are sharing the same SQL Objects when all objects are local to the sub and I always thought each thread had it's own memory to work with. So I thought each thread would call the sub create it's own objects in memory, but that does not seem like what it's doing. I have other multithreading processes in my application that work perfectly fine, this is the first time I am attempting to multithread in this manner where I am using the same procedure within multiple threads.
Just thought of something that I might be doing wrong. The subroutine in question is in the same class where the threads are created. Should the subroutine be in it's own class, and therefore each instantiation of that class?
View 3 Replies
Nov 13, 2009
I try to use Multithreading with VB 2005. I added a Listbox to main form and i tried to fill ListBox with 2 threads. When i executed code it told me that this is unsafety operation becasuse of ListBox is created with Main(Form1) form.
Is there anybody who has such simple multithreading example with Mutex or such lock mechanism?
View 1 Replies
Jun 8, 2010
what is the right way of Multithreading in visual studio 2008.
View 1 Replies
Aug 10, 2010
I m making a project in which it check website about there status (Online / Offline) through there status code and when project is in processing it hang's until the whole line of code complete
[Code]...
View 5 Replies
May 11, 2010
I'm using the WIA Aut. Library [URL] , trying to capture photos from 5 digital cameras (Nikon D90) USB-connected to my pc. Now, I partially achieved my goal, what I do is:
- loop through the attached devices, connecting to every camera;
- fotocamera.ExecuteCommand (WIA.CommandID.wiaCommandTakePicture) ;
- other image processing operations...
Everything works fine but... the workflow is camera1 -> connect -> grab pic. => camera 2 -> connect -> grab pic. => camera 3.....
[Code]...
View 1 Replies
Mar 11, 2010
I'm using the WIA Aut. Library [URL] trying to capture photos from 5 digital cameras (Nikon D90) USB-connected to my pc. Now, I partially achieved my goal, what I do is:
- loop through the attached devices, connecting to every camera;
- fotocamera.ExecuteCommand (WIA.CommandID.wiaCommandTakePicture) ;
- other image processing operations...
Everything works fine but... the workflow is camera1 -> connect -> grab pic. => camera 2 -> connect -> grab pic. => camera 3.....What I'd like is to make them shoot all at the same moment (...why? well, D90 waits around 1 sec. after a shoot... 1sec * 12 cameras * 500 photo sessions.. :'( )I told myself... what's the problem? You can create "shooting-threads" while looping through the device then launch 'em all.Done.It's still in a 'serial' way... :-(((Why? is executeCommand() a synchronized method? If I madly-fast click on two 'grab pictures' button of windows XP WIA dialog it works.. Is there something about .NET multithreading I don't know?
View 5 Replies
