Backgroundworker Runs A Object's (with Events) Method
Dec 19, 2010
I have a class that is used as follows:
Create an object
Run the RunIt method
The object runs some code and sometimes raises Event1 and sometimes Event2
I want to run that object using Background worker
Programming the app I wasn't sure of the code so I created the VS project shown below so I could make this post
Many questions:
Which routines in the code are run on the worker thread?
Is the object created on the worker thread?
And are its events run on the worker thread?
How to handle the Cancel. The way I did appears tp work except that
e.Cancelled does not return as true (Done is displayed).
And suppose the object didn't have events how would I handle Cancel?
Is there a better way to handle the basic problem?
I wish the code was shorter but wanted to be sure I prsented the problem.
Option Strict On
Option Explicit On
Imports System.ComponentModel
[Code].....
View 4 Replies
ADVERTISEMENT
Nov 6, 2010
Of course, it's nice enough to unfreeze itself when the task is completed. I have must at looked at this code for 2 hours, and still can't find the bug.
Imports System.Threading
Public Class Form1
Dim PathAmount As Integer = 0
[code]......
View 2 Replies
Mar 22, 2010
A winforms dialog is using BackgroundWorker to perform some asynchronous operations with significant success. On occasion, the async process being run by the background worker will need to raise events to the winforms app for user response (a message that asks the user if they wish to cancel), the response of which captured in an CancelEventArgs type of the event.
Being an implementation of threading, I would have expected the RaiseEvent of the worker to fire, and then the worker would continue, hence requiring me to pause the worker until the response is received. Instead however, the worker is held to wait for the code executed by the raise event to complete.
It seems like method I am calling via the event call is actually on the worker thread used by the background worker, and I am surprised, since I expected to see it on the Main Thread which is where the mainform is running. Also surprisingly, there are no cross thread exceptions thrown.
View 1 Replies
Sep 14, 2009
I have designed a class for posting data to server, which is a time consuming task so that i have used background worker in my application. instead of repeatedly using backgroundworker in my application, i decided to add it to my class and generate two events PostWorkerReportProgress, PostWorkerComplted for my application
View 1 Replies
Nov 7, 2009
I have a progressbar that works with the backgroundworker. How can I let the backgroundworker work with methods that do a foreach loop in other classes?
View 1 Replies
Oct 26, 2009
I have an object that is defined as a global variable based on custom class. Within that class I have an event that gets fired a certain intervals. These events are fired on the same thread as where the object is declared. How do I create a global object, but have the events within that object fire on a separate thread?
View 2 Replies
Nov 16, 2011
I have a BackgroundWorker in a vb.net program that is doing a lengthy data import routine. I want to modify its RunWorkerAsync method so that it fires a custom event on completion of the method. (So that a method in an automated process can respond to the event and resume its work). In a sense I want to 'extend' the RunWorkerAsync method to add an extra line of code--but I can't 'see' the code in the method (to just add the line raising the event) because BackgroundWorker is an MSDN class from Microsoft.The only solution that I can think of is to 'wrap' the background worker class in a wrapper that calls the .RunWorkerAsync method and then raises the event.
Public sub wrapperMethod()
myBackgroundWorker.RunWorkerAsync()
raise customEvent
end sub
Is there a design pattern that I might use? An easy way to address this with the .net language?
PS: Unfortunately, I'm automating some clanking legacy software and backgroundworker is used in many locations, so wrapping the backgroundworker will be a bit of work and may open bugs.
View 1 Replies
Jan 11, 2010
I have a backgroundworker that needs to contact a webservice. But when I run the background worker it just hangs forever at the line where I call a method of the webservice. I suspect this is because the webservice is defined at class level.
View 17 Replies
Jun 10, 2012
I have an application that interacts with third party COM objects. A method of the COM object that I call will sometimes stop responding. I created a Backgroundworker thread to call the function and I am trying to monitor it from my main thread to kill it if it hangs. I have additional code (not supplied) that tracks the processing time using system.timer from the main thread and I raise an event if it exceeds my threshold (this part is fine). This is when I want to kill the thread and stop code execution. The problem is.. if I use the cancelasync method it will just pend since the code execution is stuck on the function call.
The particular function call in the code snippet that hangs is "objCOM.SendDataToServer()". It typically takes 1-3 seconds to return, but if it gets no response it will just hang indefinitely and won't return at all (no errors just hangs).. there is no timeout... and since I don't have access to the source function I cannot supply one. I tried the .dispose() method of the thread, but apparently that doesn't kill it and neither does cancelasync. I just need help figuring out how to KILL this thread so I can reset the server connection and call the function again.
Public Class COMobject
Private objCOM as new acs.manager
Public Sub CallComFunction()
[code]....
View 1 Replies
Apr 13, 2011
I am trying to run a backgroundworker to load data from my DAL (which is available in another class). I want to keep the UI available and not have the "locked up" feel while the object is loading.When I create a simple backgroundworker and Sleep the UI stays responsive and my controls can be updated after the sleep. As soon as I replace the sleep with a call to instantiate the object from my DAL, the UI locks up. Is there someway I can instantiate this object using the background worked and keep the UI responsive?
When the situation object is instantiated it could take several seconds for it to load completely, during this time is when the UI is locked up... It does eventually load just fine.
Private WithEvents backWork As New BackgroundWorker()
Dim sit As Situation
Private Sub btnLoad_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles btnLoad.Click
[code]....
View 1 Replies
Jul 29, 2011
I am getting following error whenever I want to use IIf function inside entity framework query.
LINQ to Entities does not recognize the method 'System.Object IIf(Boolean, System.Object, System.Object)' method, and this method cannot be translated into a store expression.
View 1 Replies
Nov 21, 2010
There is a popup window which is rendered using xslt (no aspx page) on click of button, during this window load and close events I need to manipulate the text exist in the textarea of popup window. Having said I need to store the list words (key,value) for validation and spell check so I just declared a dictionary/hashtable object in common class (globals.vb) where i could store (add and retain values until I click close window, there could be couple of in turn calls to other methods of popup window) and manipulate as expected but whenever I reset the dictionary/hashtable (objDic.clear()) on popup load and close, it resets the concurrent users dictionary also.
Note :
1.Dictionary is declared as Public in Public Module (Globals.vb).
2.Dictionary manipulation happens inside the shared method (that is in turn calls to shared method of popup events).
View 3 Replies
Aug 13, 2011
I'm trying to code a class of RandomNumber. One of the class methods needs to populate a "List (Of RandomNumber)" ... which was passed as a parameter to the method ... with 10 random numbers between 1 and 50. DEAD SIMPLE :)
View 6 Replies
Apr 16, 2010
What do I need to convert?
Dim CEESearchByAppNo = From CEEsearch In dbCEE.tblScanneds _
Where CEEsearch.AppNo = iAppNo
[code].....
View 5 Replies
Mar 11, 2009
following error message:
Method not found: Void Excel.Range.set_Value(System.Object,System.Object)
View 4 Replies
Nov 25, 2009
I have a number of UserControls that have the same event .
When I use an Object instead of UserControl, I can not use Addhandler.
Here is the simplest example of my problem: In this example error is "TextChanged is not an event of Object"
Dim obj As Object = TextBox1 AddHandler obj.TextChanged, AddressOf text_changed_event I have to use this structure, because in a FOR loop I use some different UserControls as obj. All UserControls have the same event.
Is there a way to use this structure without error?
Maybe there is a way to define a new object that covers all my UserControls.
View 8 Replies
Feb 10, 2011
I have a number of UserControls that have the same event .When I use an Object instead of UserControl, I can not use Addhandler.Here is the simplest example of my problem:In this example error is "TextChanged is not an event of Object"
Dim obj As Object = TextBox1
AddHandler obj.TextChanged, AddressOf text_changed_event
I have to use this structure, because in a FOR loop I use some different UserControls as
[code]....
View 8 Replies
Dec 14, 2009
in my button click event i ececure
If BackgroundWorker4.IsBusy Then
BackgroundWorker1.CancelAsync()
End If[code]....
after proceess completed if press the button again.i got the following error msg
This BackgroundWorker is currently busy and cannot run multiple tasks concurrently.
View 6 Replies
Jun 23, 2009
I'm using a com object in my vb net application. I'd imported the com library and everything is fine.But the object does not raise events, None. I need to know if there is some way to achieve that it works.
View 6 Replies
Sep 19, 2009
In a reply to one of my posts, a user said I should create an event for Textbox1.TripleClick.So, I would need to create an event.My problem is, how do I create an event for a textbox so that the event shows up in the textbox events?
View 10 Replies
Aug 19, 2009
I have a custom datagridviewcolumn in which i've added an event.The problem is, I can't work out how to see who has subscribed to the current column object's event and add those subscriptions to the cloned column object.
I get around this problem by asking the calling program to pass the address of the handler to a delegate in the custom column, instead of adding a handler to the event.
View 2 Replies
Feb 6, 2010
I have an issue with usercontrols that has been puzzling me for a while. I think I must be overlooking something and many hours of web searching haven't resulted in increased insight.In my main program I have defined several events, that may be raised at certain times. e.g.: Public Event FlipBackgroundEvent As EventHandler
View 15 Replies
Mar 30, 2011
Problem that you may have when dealing with two objects that are raising some events. Here, to make it obvious, I am closing the form, but the problem can be experienced with any other 2 classes event. First, what is the problem !
Let suppose that by pressing a button, you want to raise a custom event, then execute a method and then close the form
In that case, you may use a code similar to this
Event BeepIt()
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
RaiseEvent BeepIt()
[CODE]...
View 14 Replies
Jul 28, 2010
I've been thinking about my options when it comes to events in vb.net.What I'd like to do is to track events that are fired in an application without explicitly declaring them with 'handles' sub. Here is a pseudo-[code]....
Yeah I know, not quite working, but is there any way of implementing something like this in vb.net? My end game is really to be able to monitor events fired in many objects from another object, isn't there a more maintainable way to do that then to add a special sub in each object that handles the event that I want to catch? I need some way to let one object handle events fired in other objects without a special sub, the AddHandler goes a long way, but I can't really use that dynamically like so:[code]....
View 5 Replies
Oct 27, 2010
Following up on my question yesterday to deepcopy an object with events in C# and attach the events of the original object to the Cloned copy is pretty easy, you just set the Event declaration in the Copy = the value in the original. Deep Clone when events are attached. How do you do this in VB.Net? (Using .Net 2). Maybe there was something with reflection where you can examine what events are bound and somehow transfer those to the new object.
View 1 Replies
Oct 17, 2011
I want to use One routine to handle multiple events & i want to give the list class object to the routine handle clause in vb.net. Is it possible? I have 100 buttons on my web page & i want to handle click event of each button. I have same coding on each button but the only difference is that, which button is calling the event handling routine. So i want to make one sub routine for handling event of all my buttons.
I can solve this by writing each button name in the handles clause like - Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ImgRCP_26.Click, ImgRCP_27.Click,. But it is so lengthy procedure. So that why i want to handle my button in the arraylist. How to do this?
View 1 Replies
Apr 3, 2009
may I just ask a seemingly simple question for which I can't find any solution throughout all the VB.NET documentation: I have to call a (non-static) method of another object (instance!) based upon the name of the method (given as a string).
View 1 Replies
Nov 5, 2010
I have a form and I am calling a method from a module in that form. However, how to do i call the object into the method, since Me doesn't work.
Example:
in the module:
Function printname()
Console.WriteLine("Form called with is titled:" + me. text)
[code]....
View 7 Replies
Apr 21, 2012
I have a method called ADD in a class that connects to a database. The database class name is XDB. I also have an object named XXX in it's own separate class with properties.One of the instructions for the Button named ADD click event is:
'Call Add method passing in the XXX object
So this is how I coded:
'declare a variable X as an object instance of XXX
Dim X As New XXX[code].....
I know it's wrong since it doesn't add the XXX and the form doesn't close but I don't know what I'm doing wrong.
View 6 Replies
Sep 15, 2011
Calling method in anonymous object?This works:
Call (New MyForm).Show
View 13 Replies
