Net Not Responding, Application.DoEvents And Threading?
Mar 8, 2009
My mdi VB.Net application performs a long operation on some data. Ideally I should use a separate thread to prevent the dreaded "Not Responding" message.My problem is if I use a separate thread users then have the ability to click on other controls in the application which can directly affect the operation my background thread is working on, creating an error.
Is there any way to prevent all the mdi windows, toolbars and other controls from receiving mouse clicks and keyboard input during my background thread's operation?
Or is there a way to clear the message que before performing a Application.DoEvents?
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Feb 12, 2012
here is my script:
Private Sub UpdateThread()
Dim AppDir As String = Application.StartupPath()
My.Computer.Network.DownloadFile(MyUpdate.UpdateFetchURL,
[Code]...
It does perfectly the UpdateThread task, but program just hangs.
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Aug 2, 2011
I have a windows forms application written in VB.NET which scrapes information from serveral web pages (who doesn't right)? Anyway, I am having problem with one particular site where partway through the page navigation my application hangs. When I press pause (or break) in the debugger, it stops on a call to System.Windows.Forms.Application.DoEvents.
Resuming execution shows that it really is stuck on this line (it does not reach the next line of code). It also hangs about the same point each time I run it (at least its consistent). Since System.Windows.Forms.Application.DoEvents yields to other threads on the same processor and then resumes execution of the current thread, I think the problem is that some other thread is not behaving well (not returning from some event handling code). I thought Windows 7 was pre-emptive, which makes me
doubt that theory but I really don't know.
[Code]...
The program scrapes somewhere between 12 and 14 pages before it gets stuck on the call to DoEvents. Does anyone have a clue why this would happen? Why would any call to DoEvents hang?
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Jul 18, 2011
i made an application for serial communication. for this application i need to set delay time. during this delay time i m doing some other task. So for those task i need to take back control from delay function, for this purpose i am unsing Doevents() function.Its work fine On other OS (XP, Windows7 32/64-bit). But Application.DoEvents() function halt and crash in windows vista.
Private Sub TimeDelay(ByVal DT As Integer)
Dim StartTick As Integer
StartTick = Environment.TickCount()
[Code].....
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Jun 6, 2011
Any good alternative to using DoEvents in VB.NET
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Dec 22, 2010
I am re-posing this question because the prior post has gotten really full of side issues so I fear the main problems has been lost.I have a windows forms application written in VB.NET which scrapes information from serveral web pages? I am having problem with one particular site where partway through the page navigation my application hangs. When I press pause (or break) in the debugger, it stops on a call to System.Windows.Forms.Application.DoEvents.
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Dec 15, 2009
how to exit out of the Application.Do() as i am hanging in that .Here is a sample of my code.
Imports PDFCreator
Imports System.Windows.Forms
Public Class Form1
[Code]....
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Jul 25, 2009
I am not very familiar with VB.NET so I don't know if this is possible.Some code I am working on is setting the properties of a very large class. In the setter of each property an event is raised to indicate that the class data has changed. An event handler then serializes the instance of the class to a database.Obviously I do not want this to happen after each property is set, so I need to either have a delay before saving, or something else.I am keeping a large list of instances in a cache implementation already, so one option would be to only process the cache every now and then and save all unsaved instances in cache to the database.So I tried to see if I could derive a class from Application (and override DoEvents), but it is NotInheritable, so no luck there.
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Dec 11, 2009
I have a unique situation in that I've developed a VB.NET application for AutoCAD. The way this works, you build your project into a dll and utilize AutoCAD API references when designing the project. From AutoCAD, a "Netload" command will load your dll into it's namespace to run. AutoCAD then essentially takes ownership of your application from here on out. The application is ran using a command defined in a method's attribute:
<CommandMethod("CommandNameForApp")>Public Sub MyCommand()
'Code Here
End Sub
Due to the heavy load of processing loops as it evaluates AutoCAD drawing data, processes this data, and generates many, many Excel reports, I've added a boolean property called Cancelled to my Progress class. When the user cancel's the process, this is seen by the process and further evaluation is ended and everything is cleaned up nicely. In order for this to work though, I have to implement Application.DoEvents. Without it, the Cancel feature will not work at all. With it, now instead of allowing the application to stay loaded, the Command method is fully closed.I have added a go-to point and simply verify that the application isn't closing because of a user-cancellation event. Here's what it looks like now:
<CommandMethod("WireShop")> Public Sub WireShopApplication()
'Initialize Configuration File Data
'Initializes ValidBlocks, MarginDistance, WindowDistance, and HelpFileName Properties
If ConfigurationFileInitialization() = False Then Exit Sub
[code].....
In my opinion, this seems a little hokey. However, I'm not that familiar with exactly what Application.DoEvents is doing in the background to understand how to "head it off at the pass".
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Nov 9, 2009
I'm trying to automate the process of logging into twitterfeed.com, and filling in the information (the feed url and twitter username are pulled from textboxes). I had it mostly working the other day, even if it is a bit sloppy (the only way I could get one button to click is to send 50-some tabs). However, lately it seems to enter in a sort of loop. When I pause the program, Visual Studio indicates that it is the Application.DoEvents in the Private Sub "wait" that is still running even after it should be.
Public Class Form1
Private feed, username, temp As String
' Code stolen off of a website as an alternative to sleeping, or trying to do a timer + while combo like I had been doing
[Code].....
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Mar 4, 2010
I'm running in to a problem that I was able to fix with Application.DoEvents, but don't want to leave that in because it might introduce all sorts of nasty problems. Background: Our app is primarily a desktop app that makes many calls to a web service. We control everything but changes to the overall system design are not going to be seriously considered. One of those calls, Calculate, is used very often, and occasionally can take a few minutes to process all the data to return valid results.
[Code]...
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Mar 15, 2009
We just spent 300 man-hours fixing a buggy application in the field. It all came down to calling Application.DoEvents (re-entrancy problem).This was not caught in design reviews, code reviews.The code was inserted two years ago with the first version; the application was always "flaky" but recent changes exposed the re-entrancy problems to a greater degree. This incident is the second time in our organization that Application.DoEvents caused failures and multi-man hours of debugging.It was discovered in this case by simply noticing the call,buried way down in a complex event handler for an asynchronous task.What do you suggest to prevent this issue from happening again:
Add checkin gates to source control?
Developer training?
Code Analysis rules (why is this not already a built-in rule?)
How to I enforce a coding practice?
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Jan 21, 2012
this is my first post and my knowledge of Visual Basic is still in its infancy (this is my first real attempt at app that is any use) however I am trying to develop an application to delete user profile and home directory folders.
I have the application working but the problem is with the application hanging (I understand this to be due to it running as a single thread and the main form gets ignored while the deletion is occuring) during the deletion process, I have tried various ways to resolve this such as starting the delete procedure as a new thread but cant get it to work without the hang.
[Code]...
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May 7, 2009
I can pause the application and see that it thinks no threads are running so no call stack. The other projects in the same solution are all responding fine, just this one stalls. I can not think of any way to work out what it was doing at time of stall, I have no event logs, no breakpoints, there is no particular thing I can check for in my own logging system (which is quite extensive) that shows where/why/what the application is hanging for. Any clues on how to solve/investigate? To add, this is on a Vista box, but not able to move the system to anything else (source controlled) until I can find out what this is. Its an avenue I can go down if required however.
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Feb 2, 2012
I'm using VB 2010 Express with a local Access DB. On the form I have a DataSet, a TableAdapter, a BindingSource that points to the DataSet (and the DataMember is the same table as the TableAdapter), a BindingNavigator that points to the BindingSource and finally a DataGridView that points to the BindingSource also.
I have added a Save button to the BindingNavigator. I want to enable / disable the Save button depending on whether there are changes in the data to send back to the Access DB. I think this is the code, but I am not sure if I'm really doing what I think I am (i.e. I am concerned I will assume something turns out to be wrong) or if there are better ways.
I am also uncertain what event to use to respond to. I have guessed at CellLeave, but I could be wrong and there might be much better choices. Finally I've been told that it's different if it's a DataTable, but I do not know enough to determine when something is a DataTable?
Private Sub CompClass_DataGridView_CellLeave(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles CompClass_DataGridView.CellEnter
Me.BindingNavigatorSaveItem.Enabled = Me.Component_MI_DataSet.HasChanges
End Sub
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Jul 31, 2009
Whenever my application goes into a very long loop, the form stops responding. How can I stop this?
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Sep 19, 2011
Im building an application in vb 2010 which uses window media player component. When I run the application in debug mode and Press Play button, the application hangs up and stops responding. When I press PAUSE button in vb 2010 the line it shows is
mediaPlayer.URL = curl
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Apr 6, 2009
When starting my application, I have a couple of classes which are required to read certain files in order to create a set of default data. The logical place (to me) to do this is in a Shared class constructor; the idea would be to throw a class-level event if the reading of the defaults file fails. Unfortunately, this does not work as attempting to access such an event, in order to attach a handler to it, fires the class constructor before the event has been attached. In a failing case, the constructor starts, fires the fail event, the constructor completes, and then the event handler is attached, after the event has fired.
The only other solution I can think of is to give the class a "typeInitialisedSuccessfully" boolean property and put a try/catch block around every call to construct an instance of the class, which seems unnecessarily kludgey to me. Can someone suggest a more elegant solution?
EDIT: Because this is a fundamental Class, used in one form or another across nearly all of our software tools, I would greatly prefer a solution that will notify future programmers that the type initialiser needs to be called, which is why I initially went towards the Shared Constructor as a solution.
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Apr 14, 2011
In my application, the user can create a word document from a word template with dynamically added text and data to it. This happens on a backgroundworker so that the application doesn't hang during the process. This all works fine and the word document opens correctly when finished. Now if the user leaves the application to do something else, in most cases when they come back to it, it has frozen. It's still responding/running in task manager but the interface is frozen. In debug mode, it never freezes and so I can't catch the exact moment when the freeze occurs. My backgroundworker is disposed of when complete and I close everything related to the word object.
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Dec 12, 2009
I'm uploading an image to url... etc. The trouble is my application stops responding for 5-10 seconds while the image is uploading. I want to use multi-threading to stop it doing that but I'm confused with the whole way to use controls with backgroundworker. [code] I guess its the textbox which is causing the problem.
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Sep 9, 2009
I know there are many cases when it's best to multi thread an application but when is it best to multi thread a .net web Application?
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Aug 31, 2011
I have some functions in a web application that do a lot of calculations and as a result have high CPU usage which affects the rest of the application when other users are accessing it. I have tried background-worker to no avail , the only thing that seems to work in using another thread and setting the priority to low, can the UI be updated from a worker thread? specifically I am trying to bind a grid to a dataset processed in the worker thread
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Jul 18, 2012
i have a vb.net application that plots 16 plots immediately, the plots data are realtime. the 16 plots must draw the points at the time they receive them (must be no delay), to do that
1- i made a timer with ticks at 50 ms.
2- at each timer tick call the plotting function 16 times (with a graph name as parameter)like that: [code] it made a big delay, when i used threading the application became unresponsive.
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Jun 15, 2009
I am working on adding multi-threading to my application. I have done two applications using multi-threading following a tutorial of sorts, and modifying the code to "get my feet wet."
This is the first time I am trying multi-threading within my own application, and I feel I should be beyond this type of problem, but after a 3 hour search on the forums, I can not find a solution, so I am posting this thread.
The section of code with the error
vb.net
Imports System.Threading
Imports SldWorks
Imports SwConst
[Code]......
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May 4, 2011
I have a console application that is built in VB.Net. Now I have a timer in that application. All I want to do is at a particyualr time i will call another exe (which is built in VB 6.0) and again get the control back to this console application. Now what is happening is that I am being able to call the second exe from the console application, but then the control is not returning back to the same console application.
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Mar 2, 2011
I have written below console application in VB.net. My intention is to write an application that triggers every one minute and perform some task. But when I run this application it is consuming 50% of CPU.
[Code]...
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Apr 5, 2011
I am working on an application that is taking pretty long to execute. I started playing with mutli-threading and it seems to have greatly sped up my app. Problem is that threads are still executing and the rest of the code executes before the threads finish. Here is my
[Code]...
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May 13, 2012
I have this little application that is using a System.Threading.Thread.Sleep, application runs great but Windows thinks the application is not responding even though it is running.
[Code]...
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May 2, 2009
I have one applicatin developed in my ap i have two main functionalities
1)Copyig Folders & Files from one source to destination
2) And I am showing status of copying in richtextbox and progrss with progress bar
Here i need to use threading bcz i am copying files from one server to another server and some large size files while copying my application always gone to stuck and i am not able to see status of copying and progressbar so how i use threading in my applicatio to put two functionalitis in two seperate threads.
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May 18, 2009
I am using FileCopy and My.Computer.FileSystem.CopyDirectory to copy certain files and folders. The problem I have is that when this operation is being carried out for a large directory (say 1gb or so, probably less) - the program goes into a Not Responding mode until the copying is complete. If you let it sit there, it will eventually resume itself once the copy is complete; however, my end user is going to think the program crashed.
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