Use Threading.Tasks.Task To Kick Off A Background Search While User Types, But After They Pause?
Oct 3, 2011
I have a lengthy XML file that I want to search based on text that a user types in. Because it's lengthy, I want to wait for the user to stop typing for 250ms or so before I actually start searching in the background. I tried to kick off my Task, having it sleep for 250ms, then check if my CancelTokenSource had canceled because another character was typed. I'm not seeing a cancellation, though, so I end up seeing my results flash several times as the queued up search tasks complete, one after the other, after I finish typing.
how the threading within vb actually works. am i of the understanding that every time you create an event, through a button control for instance, that this infact creates a seperate process which will run independantly to another. say for instance you had two buttons on a form and each contained code which took 5 seconds to execute. if i were to click one button into action and then the other with a second, would the two processes run alongside one another or would i have to wait for the first code to execute before the second button could be executed?
I'm currently attempting to use a .NET WebBrowser to display help information (stored locally in html files) for an application I'm writing, however I'm experiencing two problems, both related to hyperlinks.
Firstly, I have a search function which returns the correct URL in the format file:\C:... I can copy and paste it into a browser, and it will navigate there. Yet clicking on the link within the control itself does nothing at all.
Secondly, the HTML files all contain relative paths to other HTML files. These of course do not work as I just end up with file:\C:help.html which gives me a 'webpage is unavailable.' But I can't think of a way to get it to work without parsing the HTML file and concatenating the path to the directory on to the front of the link.
Just to clarify, in the first problem I am dynamically building a search result page as the user types. The HTML contains several results similar to this (yes, it's unfinished, I'm just showing you the link part): [code] Now, when I click on that link in the control nothing happens, it doesn't give me a 'webpage is unavailable' or take me to the actual page. Saving the HTML, however, and opening it with Chrome, IE and Firefox works fine.In the second problem, I have a different help file for different sections, each containing relative links to several others. VB picks these up as direct paths, and attempts to go there from root, i.e file:\C:file.html. The only solution I can think of is to parse the file and use WebBrowser.Navigate(Path.Combine(pathToDirectory, nameOfHelpFile.html), which seems a lot more inefficient than it should be.
The question is when I do task.Wait(4000, cancel.Token) this should ultimately fail as the ContinueWith task won't complete within the timeout. It seems the Wait only applies to the Task and doesn't take the chain into account, how can I have it wait until the "chain" is complete?
I have written a task script using vb.net that have thread used in the code, the problem is how i can know when will be finished all the threads so i can return the success result.
Is there a way to pause a background worker? What I need to do is pause a background worker when it encounters a file error, wait for a few seconds, and then carry on.
Currently I'm using System.Threading.Thread.Sleep(5000) to let my app pause/sleep for some time. This works great but I can't open my app anymore when it's sleeping and it uses about 25% of my CPU. I guess there must be a better way to do this. I also tried using a timer but that didn't work out to well for me..
I have created a background worker to go and run a pretty long task that includes creating more threads which will read from a file of urls and crawl each. I tried following it through debugging and found that the background process ends prematurely for no apparent reason. Is there something wrong in the logic of my code that is causing this. [code]Also my main thread runs a forms from where this background is called to run but the main thread is supposed to wait for the background process to end unless the user selects another option from the main form.
I have form with a button and when the button is clicked it opens another form called form2.
On the form2 load event I'm grabbing some info from form1 and loading a crystal report and passing the report some parameters , then printing the report. Once the report is sent to the printer the form is closed.
Can I put this process on a background worker to improve the printing performance of my program and could someone point me in the right direction for doing this? I've found some examples online but I lack the vision to see how those examples could work for me.
Ineed a VBS script that removes all scheduled tasks which start with a specific string.
For example, delete all scheduled tasks which start with "My Application Tasks..."
I wanna use this VBS script in my application uninstaller so all tasks created by my application are removed at the uninstall time, however am not familiar with VBS.
I am building a game project for a school project. User gets points for completing certain tasks. I have it all coded - curious as how I should do high score table. I was thinking an Access DB, but that seems like total overkill. Does XML seem reasonable?
VS 2008 crashed for about the 3rd time today. I had added several task list shortcuts and User tasks to my task list and they all disappeared. Where did they go? Doesn't VS save this stuff somewhere? If you close VS do you lose all your tasks that aren't in TODO comments?
I would like to get my program to run in the background. The EXE file I have created, I want it to run in the background and yet do not want to show the user that the program is running. Like I don't want to have the minimized screen on the task bar. Can I do it in my VB.net program.
i have a win form, where i have a block of code which keeps checking for entry in database, every say 2mins, now i want to avoid using timer control, for performance reason, can the same be achieved using background worker.
I have been pulling my hair out trying to get this to work. If I step through the code in debugger it all works great. My problem is if I just run it, only the last task responds. I'm guessing I am overwriting the background working or something. I am sure I am doing a few things wrong but my code is now messy as I tried many way while searching. I know of the threadpool and .Net 4.0 tasks but having a hard time getting to do what I need.
Basicly I am writing a program (trying more likely) that takes a list of computers and pings then, then checks their uptime and reports back.This works fine in the UI thread (Obviously that locks up my screen). I can have the background worker just do this, but then it does each computer 1 by one, and while the screen is responsive it still takes a long time.
So my answer was to have a for loop for each server launching a new background worker thread. My solution does not work.I have seen other threads that I could do it, but I need to use with events to call code to update to UI when each is done.
What is the most simple way to do this?
Here is my code. Most is just copy paste + modify till I get it working right.
So In the main class I have the testworker.
(I tried using Testworker() but it said I could not do that WithEvents)
When I click the button the list loads.
Private WithEvents TestWorker As System.ComponentModel.BackgroundWorker
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles Button1.Click
This is what I want, I have 12 progress bars and I want to run a background task to ping IPs and if it can ping them it starts a timer is this imposable to do?
I'm trying to save what the user types in the vb code Dim user as Inputbox("") for example in a .txt file i can save the textbox and listbox but i cnt figure out how to save the inputbox i really need this to be saved the most.
On my main form i need to pop up a sub form and await user input before proceeding. I am able to pop the form but not able to pause code excecution until the user input is there. Here is what i have tried:
If chk_athor_cobb_scholi.Checked = True Then Vselect.Visible = True While Vselect.ex2 = False
[Code].....
The problem of course is that the while loop causes a crazy infinite loop and locks the program down during excecution. How do i await the user input?
I'm tryng to figure out a way how I can stop my code from running while I wait for input from a device.Networked device that sends data to .net app.I now wish to prompt the user to answer a 'Continue' questoion and select either 'Yes' or 'No' on the device. This is transmitted to program over netstream.I want the code to pause though while waiting for an answer as different routines are run dependent on the answer.
I want to be able to run a thread and then at a certain point pause it and wait for the user to enter some text into a text box and then when they press submit i want the program to run again from where it left off.
I'm in a bit of a quandry. I am trying to build a simple search form where the user selects the column title and in puts the criteria then clicks the search button. This is the code I am using
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click details = ComboBox2.Text 'column name selected by user specifics = TextBox1.Text 'criteria input by user
I have a combo box on my application (working with VB.net) called CmbAttendantstatus. I have sent the dropdownstyle = dropdownlist at the Properties level of the combobox.
There are 200 field types e.g; Current Attendant Ever Attendant Never Attendant etc
The issue is I can only select one from the list, fine, but I want to be able to type the first letter on the combobox and it takes me to the nearest field type rather than looking through the entire drop list. For example I want Never Attendant, I just need to type N and the drop list takes me to anything starting from N and if I add E for example any field starting with NE shows up for selection. Presently, when the dropdownlist is selected you are not allowed to type anything...
1) Why the pause button and also the pause command does not exist in VB 2010 Express?
2) I have some solutions under 2010. In 2 or 3, while debugging, I can change instructions without restarting the application. In others, I cannot change anything (Is like readonly), Looking in 'My Applications', Tab 'Debug', Option 'Configuration' I can choose several Options. In the applications I can debug, the default is 'Active (Debug)'; in the others is 'Active (Release)'. If I change the options, the word 'Active' remains attached to the original option.
I have a search function in my app which is a groupbox with a textbox that contains the search keyword and a couple of radiobuttons. Do I have to create a keydown event for every single radiobutton and textbox? Or is there a better way? I tried making a keydown event for the groupbox but that didn't work.
If your interested, this is my
Private Sub Search() Dim textBoxContents As String = txtBoxKeyword.Text Dim keyword As String = Nothing
The following is the code that uploades a bytearray into a file DSN on our mainframe. It works very well.What I want to do is upload the jcl which should then start to execute.I used to be able to do it through WININET, but I want to get away from that and use the better FTP commands in vb.net. [code]
Can somebody form an idea on how to architect a web application which will kick start an independent process in the server which can perform data uploading function from flat file to Oracle table. This independent process should keep running until it finishes its job regardless of the web application's sign out or timeout issues. The client is a .aspx page which uploads the data file to server and then triggers the independent process in the server.I want to implement this in ASP.NET, VB.NET, VS 2003.
