VS 2008 UI Threading - Move/interact With Both Forms While The Loop Is Running ?
Oct 17, 2009
When it comes to threading. I've managed to adapt one of JMcIllhinney's backgroundworker codebank examples to somewhat suit my needs, but not completely. I have a main form, and a second form that appears while I'm running through a for loop. It informs the user what is currently happening. I set up a backgroundworker that allowed me to continue to use the main form during the for loop, but the other "status" form was completely frozen, and any labels or graphics were shown as white boxes. I am struggling to figure out how to be able to move/interact with both forms while the loop is running.
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Feb 23, 2011
So I am currently using the method of combining a timer with a WebBrowser control to constantly check if some particular text has appeared in the WebBrowser control on my form. The text is dynamically generated after some arbitrary amount of time depending on the user's internet connection speed. (I'm using DOM to do this). The code to check for the HtmlElements lies within a function, which is turned called by the timer.
I find that this is kind of crappy and occasionally lags the UI interface, if not making the entire program behave sluggishly. I have been thinking of just using a simple while loop in a worker thread to take care of the issue, but I understand that new threads cannot interact with the UI thread directly (including controls); they have to call wrappers that are present within the UI thread.
So my question is, can you declare a WebBrowser control and still interact with its HTMLDocument properties if you declare it within a worker thread? I don't want the while loop to be executed within the UI thread (by using a wrapper), since that would defeat the purpose. I would also like to avoid DoEvents() as much as possible...unless that's the only way to do this thing?
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Mar 12, 2010
This part of visual basic is new to me. How can i make multiple forms that each operate on different computers but can interact with each other and influence each other over the internet?
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Aug 3, 2011
At user login, launch an app I have created. This app opens a web site in a webbrowser control, logs the user in to the web site, and parses links from the resulting web page. These links are links to launch citrix sessions on another farm.
Create another app that appears on the start menu for the logged in user. User clicks on this app, it communicates with the launch app to basically click the href associated with the citrix app within the webbrowser control. Then this app will go away...
I have already coded the first app and figured out how to click links within the webbrowser control. What I can't figure out is how to go about implementing the second app, that runs as a separate app, but communicates with the first app to do its business. I see a plethora of options such as MFC, AppDomains, RPC, and so on. My question is which is the best practice to have one app interact with another and have the other app take actions based on that interaction? I prefer to stick completely to vb.net.
A good example of how I would like this to work - a web browser (IE, FF, whatever) is open on the desktop, user clicks a link in an email, link opens in running browser. An action in the mail client causes action in the browser.
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May 17, 2010
I'd like to make a simple program where my form consists of a textbox and a button. Here's the ide in a nutshell:in form1_load I invoke the sub:
private Sub LoopingLesson()
dim i as integer=1
while true
[code]....
what I want is when i hits certain value, like let's just say i is divisible by 365, then the 'while' looping will stop, and a message box saying "target reached" appear. then after I click button1, the looping will resume until it reaches the next number divisible by 365, and so on.
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Jun 14, 2011
I'm using SHDocVw.InternetExplorerClass to scrape a webpage. It works fine in XP, but when I try to run it in windows 7 I get an error:The interface is unknown. (Exception from HRESULT: 0x800706B5)
When I run visual studio in administrator mode it works fine, but the published application has to be run in administrator mode too, which isn't acceptable.
Is there any way to get around running the application in administrator mode?
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Mar 12, 2010
Have a Windows app that needs to interact with a stand alone program that is accessed using cmd.exe. From Windows app, I can execute cmd.exe but cannot interact with it. Tried SendKeys, but this only sends one key at a time (sometimes more, but inconsistent) with multiple cmd.exe windows opening. Need to be able to send a whole command (string) to only one cmd.exe window.
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Apr 8, 2011
Im working on my project. and i just asking if i can used this Property in vb. NET [URL] when i install adobe photoshop .. i see on the leff installer...something like a menu and the menu move step by step when the user move between Forms
Welcome
Serial Number
Adobe ID
Install
Finish
How i can create like this in VB .NET
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Mar 21, 2012
I have an app that the user selects a database and the user tables are displayed in a listbox. The user selects which tables to export to an Excel workbook, one for each table. There is a richtextbox that informs the user when the created files are done.
The app works and the xlsx file are created as expected. The problem is when each is finished only the last file of the selected tables is displayed in the RTB.
The form has the following Handler
[code....]
The threading is done in the following
[code...]
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Sep 25, 2009
Running into problems creating objects through reflection and then running them on multiple threads.
I just cannot seem to figure out what I need to here:
For Each WorkerNode As XmlNode In oRunSettings.GetWorkerValues
orkerName = WorkerNode.Attributes(SETTING_NAME_ID).Value
Dim oWorkerType As Type = Type.GetType(String.Format("Worker.{0}", sWorkerName))
Dim oWorker As Object = Activator.CreateInstance(oWorkerType)
[Code]...
It is causing errors at the "AddressOf" because Object does not have a method called that. Do I need to do something with an interface?
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Aug 20, 2009
after my last post i dove into remoting to try to solve my performance problem in a client-server fashion.
This works very well, but i come across a big problem which i don't seem to get solved.
I made a well known singleton servicetype on the server that retrieve all customers. Whith 1 db connection this works fine. But very often customers and i use in 1 sql instance multiple databases (for each administration a separate db). so the whole purpose of a singleton object is hereby destroys as soon i connect in my class to a different db. Is there some way to overcome this for example threading or running multiple servers (for each db it's own server-application)?
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Jun 22, 2011
I am a student attempting to learn VB.NET on my own. Today I wanted to tackle the BackgroundWorker component. I found an excellent article online: How To Use a Background Worker. I successfully completed the walkthrough and even performed the "adventorous" part that dealt with working with controls updating across threads using delegates.Now I came to a part that I didn't understand how it was working. To summarize the following code, I have a delegate that has a Label and a String in its signature. I then have a subroutine that is called on the worker thread. Inside this subroutine the delegate is created and (I guess) ran again so that it is on the same (Main) thread. Please correct me if I'm wrong here.
Here is the method is performed on the worker thread:
Private Sub My_BgWorker_DoWork(ByVal sender As Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles My_BGWorker.DoWork
[code].....
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Mar 2, 2012
I may be the only person still automating excel this way and I am looking at doing it in ways that better handle COM objects and such, but for now I just importMicrosoft.Office.Interop.Excel and go for it. Something that gave me a lot of grief at first was hanging excel.exe processes, but there are tons of resources online for fixing that. At this point I am pretty confident in my abilities to handle it.One thing I did notice and was wondering about is how does closing a windows forms application interact with excel.exe running in the background and likely more specifically the garbage collector. I have written quite a few excel automation projects and noticed that after I run my program .exe and it has completed there is an excel.exe process that hangs on until I close the pop up window from the windows forms application. Why is that happening?
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Mar 31, 2010
Below i am giving a Code snippet and my question is specifier in the bottom.
[Code]...
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Jan 31, 2009
I recently started out using Visual Basic, and I've run into a problem.I need to be able to change between my two forms when I run my program, however since I'm still rather new at this, I've been unable to figure out a way to do this.
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Jul 13, 2011
I have never interacted with Varbiles outside of the projject but now in need of it.I am developing a Windows Service Application that is multi-threaded. There is going to be a set of Global Varibles in the application that contain basic status information such as how many threads are currently running, What clients are currently connected etc.
Now I would like to develop another application as a monitor. This one would be a Windows Forms App and its sole purpose is to display to the user this information so that is can be monitored.Is there an easy way of doing this? If not I don't think I will bother as the Monitor is not essential.
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Aug 8, 2010
I have an application with two forms - a splash form and the main form. The main form reads an XML file and displays data from the file in a rich text box. While that is happening the splash form is displayed. When the main form is ready to be displayed the splash form closes and the main form is displayed. I have a progress bar on the splash form to inform the user of the progress of the load. I want to set the maximum value for the progress bar to the number of elements in the XML file. In the main form I am using a reader to count the number of elements. After I get that number I wan to update the maximum on the progress bar control so it displays correctly. That is where I am getting the cross threading error. Now I could do that in the splash form. But where the real issue lies is I want to update the progress bar value every time I read an element in the main form process to read the XML file. That I don't think I can do in the splash form as it would duplicate the process of the main form and defeat the purpose of the splash form.
I have researched this issue but can't find an answer. I have tried the delegate route but I still get a cross-threading error. I assume that is because I am cross threading across forms.
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Feb 12, 2009
Forms :: ToolStripStatusLabel and threading
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Mar 31, 2011
I have a frm_Main, which starts a thread. The thread then goes and calls a module, which has a thread.sleep() in it. This causes the mouse to freeze up while it sleeps, despite being called by the child thread. I thought this would have be on the thread time-slice? However it is causing my form to freeze for the sleep duration.
[Code]...
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Jun 17, 2012
i want to move a program that already is running, and by move, i mean change the x and y coordinates of the application on the screen. how would i go about doing this?
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Oct 10, 2011
I'm doing a project in VB.NET, in which the application will interact with SQL Server 2008 database. I know how to develop that application. But after created executable version of that application(.exe) i will install it in another machine. How will that application interact with database at that machine??
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Jan 5, 2010
Is it possible to move the cursor down in something like a for next loop? I would like to sequentially fill in cells (down a column).
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May 6, 2009
Is there a statment like Exit For, except instead of exiting the loop it just moves to the next item.[code]...
Just wondering if there is a way to jump to the next item in the Items List. Im sure most will proberly be asking why not ust use the else statment, but to me wrapping the "Do Something" code seems to be less readable especcially, when there is a lot more code.
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May 7, 2011
I'm trying to dive into what I consider a deeper end of VB.net to see how far I can go with it. I have a project created, ironically called "My First Server". The aim of this is to create a server which can handle multi clients but additionally isn't the commonly shown tutorial setup of a console application. So it is created as a Windows Form application. The main form (Public Class PrimaryForm) consists of only one control which is a listbox control. This is named LogOutput.
[Code]....
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Dec 12, 2011
I want to start building my first large program. I want to create scripts on their own and allow them to interact with my main sub. I guess if I need a "plane" in my application, that could become it's own class? If I wanted to calculate "purchases", "money" I could create a DLL? I don't want to have to change things and have to recompile my entire application every time I want to change how something works for example.
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Jan 15, 2010
I am using Visual Studio .Net 2008. I am using "Structure" statement for my work. It is working with me perfectly. I am not sure if Understand the structure statement very well because it does give me wrong answer if I change the position of "Redim" of the structure elements. My problem is the structure is using "Redim" in many places which is a dangerous procedure. I do not know how exactly to explain my problem because the structure in my code is used widely and called in many subroutines. I will try to explain with the below simple code:
[code]...
My question is: How can I move the all "Redim" statements outside the loop so that the Redim happens only ones? What does "TheCollection(Iteration + NumberOfMembers).TheResult" does take? Is it zero or what?I searched the web but I could not find a proper website or article which explains the structure. The only useful link I found is this:[url]
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Mar 27, 2010
I'm in a pickle... either that or it's getting too late in the day. How do I loop through an array in reverse without using FOR?I have an array of string values, I need to loop through these values until I find the first instance of a value then stop. I have considered a sort on the array but each query would need me to sort it accordingly (the data in the array has many instances of the strings within strings I am looking for, e.g. there could be several 'to' but I need the first, there could be several 'from' but i need the last)When I find the instance of the string, I then need to grab specific data from that string.
[Code]...
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Sep 24, 2009
I've seen loads of programs that use an icon in the system tray to let you interact with a windows service that is running on your machine but I am curious as to how this works. As I understand it, unless a service marks itself as 'interactive' then it has no way to communicate with the user's desktop and doing so is discouraged by MS (and even causes an alternate desktop to appear temporarily in Server 2008 in some cases). So I want to try and avoid doing this but I cant think how else I would do it, and even if I marked my service as interactive I'm not too sure how I could actually get it to show a notification icon in the system tray.
I assume I would have to use Windows APIs, unless just using the windows forms NotifyIcon class would work. I considered just having the system tray icon in a totally separate application that just communicates with the service via named pipes or TCP etc but I'm pretty sure this isnt how other programs do it because with most of them if you just kill the process that the service is running in then the icon disappears so it must actually be directly running from the service.
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Sep 7, 2009
I'm using Visual Studio 2008 on an XP machine and am trying to develop a web app that can interact with websites and carry out automatic tasks.One problem I have is trying to recreate the web requests for automatic interaction.
For example:I use a webBrowser control to allow me to surf a page manually. Then, once I am at a specific location, I'd like the automatic interaction to take over.Part of the website requires a log-in and exchanges cookie data.When I try to read the cookie info from the webbrowser control to build the subsequent automatic requests, the cookie content is incomplete.Upon further investigation, it appears that the site sets one of the cookies to "http only". This stops the value being visible to the webbrowser control.Is there another control or method I could use to retrieve this info?
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Jun 22, 2010
If I'm running a Do... Until or a For... Next loop in a button click event, is there a way I can allow the user to click the same button while the loop is running and escape the loop?
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