Multithreading And Status Bar - Simple "tasks List"
Apr 4, 2011
Haven't played with .NET for a while thought I would build myself a simple "tasks list" for work basically to "brush off the dust". Windows Form + MySQL
Now on form load I wanted the program to automatically try and connect to the DB. No problem except the DB connection always delayed the program launching by roughly 5 seconds. So I figured a separate thread call to take the stress from the form ... and now I'm floundering ....
CODE:
simple enough on form load display the dynamic text to the status bar label named dbStatus. Than start a new thread to the address of my database connection function. This works fine, i can even throw a msgbox() inside the function and can be told its connected. But in that same function I add the line
CODE:
Commented lines were me trying to reference it a "different" way ... but every time I run this the label never gets updated, when i step through set function the 'InvokeRequired' is either nothing or false.
But of course directly trying to access the text attribute of the label doesn't work but strangely enough doesn't throw a cross thread error either.
Hence my current dilemma ... I can directly call db.ConnectDatabase and everything works as intended .. when I throw the function into a separate thread my status label never gets updated, nor am I warned about any cross thread operations.
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 have a List(Of Byte) that is filled with bytes from the serial buffer on a SerialPort.DataRecieved Event. I then try to parse the data. Part of the parsing process involves deleting elements of the List(Of Byte). Should I be concerned about the List being modified by a DataRecieved Event that might be raised during the parsing process? I realize that probably depends on what I'm trying to do, but, assuming I should be concerned (e.g., the parsing process needs List.Count to not change until parsing is finished), how should I go about making sure any Add calls wait until the parser is done? I guess the answer is something like SyncLock, but I've never really understood how SyncLock works.
I'm trying to get this code to save the list when a new website is added, how do I get a list of collections to save a link that I designate into the list?
Private Sub ToolStripButton8_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ToolStripButton8.Click ToolStripComboBox2.Items.Add(WebBrowser1.Url)
I have a list box that contains some values. I want to checked just whether any of the item from tha list has been selected or not? If selected output should be true otherwise false.
I have the following multithreading function to implement threads fetching from a list of urls to parse content. The code was suggested by a user and I just want to know if this is an efficient way of implementing what I need to do. I am running the code now and getting errors on all functions that worked fine doing single thread.for example now for the list that I use to check visited urls; I am getting the 'argumentoutofrangeexception - capacity was less than the current size'/Does everything now need to be synchronized?
Dim startwatch As New Stopwatch Dim elapsedTime As Long = 0 Dim urlCompleteList As String = String.Empty
Now for a succesful insertion i want to notify the user about a successful save operation.....i.e,i want to display a message "Successful Save Operation"to the user. How to do this using the Status Strip?
I have a form containing a checkedlistbox, I want to be able to do a simple comparison between the checked status before and after to see if there has been any change. I have a copy of the "before" version of the checkedlist box and I thought I could just compare the two CheckedItems but it always thinks they are different, I could iterate through the entire checkedlistbox but I thought there would be an easier way. [Code]
I've got the code to display the current browser status text in the status bar but i want it to display the name of my web browser aswell. Example: Dreamincode.net - (Name of Webbrowser)
He is my code for the displaying staus text. Private Sub webBrowser1_StatusTextChanged( _ ByVal sender As Object, ByVal e As EventArgs) _ Handles webBrowser1.StatusTextChanged
when your resetting a form is it possible to deselect or not keep high lighted the item that was previously selected from the last entry. I know how to clear the text boxes but the items in the list boxes stay highlighted. Is it possible to get back to the initial setting of having nothing selected as when you first start debugging?
I'm trying to create an application that is able to find products from a XML file, which will contain the following data:EAN (Barcode as a string, not an image) Description Price Stock
So basically, I enter the EAN and my program will lookup the XML file for this EAN and will return the description of this product, the price and the stock in a new messagebox. However, I don't understand how to create a XML file, add items, remove items, edit items, and most of all: read items from a XML file.
I have a gridview in which when I click edit, update, and cancel button comes. I have a variable named status. If status=false then update should change to insert and if status=true then update should be update itself.
I need two seperate lists, which every item is Integer, String, Bitmap - and one which every item is Integer, String String. However I don't know how to do this, or even where to look - I've googled for custom objects and custom object lists. What I'm trying to do is this.Custom Object1 is Integer, String, Bitmap Custom Object2 is Integer, String, String
In one thread I'll be adding items to List1(Of Object1), and processing them, and adding the results to List2(Of Object2), however I need to be able from other threads to look at the list and say only give me the items where Integer = (my thread ID), is this possible? Any help, or even links to information that would be relevant to this request would be helpful?
Trying to make a simple browser with some simple addon's. What Ive done is setup a menu(forum) for the user to enter their email providers web address and it will save it in a xml file. When they click on the email link, it should load the email xml iformation and place that info in the tb_html.text and navigate. I keep getting a null exception and im not sure what going on here. Here is the code:
Browsers: Private Sub btn_Email_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn_Email.Click 'Load Action Dim SavedEmailObj As Storage
My program performs a bunch of task in a loop. After each task completed it saves log/status of task in a text file. The program runs fast but if there is more than 10,000 tasks it becomes slower and it takes a lot of CPU because of frequent I/O operation.
Is there a better way to save the log/status of task without making the program slower? At first i used a textbox control to store the log but the problem is textbox control can not hold a lot of text.
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 am trying to create a vb application that will create sscheduled tasks .Created a windows service and set it to start manually for now.Just as a test, when the timer expires I have set it to start 'Notepad' as a process which I can see listed under processes in the Task Manager, but cannot see it as a scheduled task.What I am unsure whether this is the right way to create a scheduled task and if it why can't I see Notepad in scheduled tasks.
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.
Dim i As Integer Dim objExcel As New Excel.Application Dim objWorkbook As Excel.Workbook objExcel.Workbooks.Add()
[code]....
At the end of this routine, eventhough the data was correctly saved to my Data.xlsx file, this routine also opened 15 EXCEL.EXE tasks in task manager.I thought that I had cleaned up before quitting. By the way, whether I write to 1 or 5 or 10 cells in Data.xlsx, 15 EXCEL.EXE tasks would be opened regardless.Is there a way to (easily and) completely close all EXCEL.EXE in task manager before leaving my application?
simple way of attaching a progress bar to the tasks of a button.When I press a button, several tasks will commence and I want a progress bar to show it's... well... progress.
I am writing a VB.NET application that creates a new task item for another user. Is there a way of having this task go straight to their task list without having to open the acceptance email ? ( Would help if such an email is not sent in the first place to avoid cluttering)I found a similar post on experts-exchange forum, though no one was able to answer that till date.I assume that can be achieved using shared Task folder but could not get good examples on msdn to work with.
I am building an application that will run through various tasks like database backup, zipping some other files and so on.I have the progress bar figured out for each individual task and I have all my tasks working.I am trying to build an interface to display to the user to show them the progress of the entire run.I was thinking like a list box or other object where I could put a green checkbox image or red x image as each tasks runs and is a success or failure.
[code]i want some help on how to use the datagridview control to perfom tasks that i usually used to perfom using a datagrid control.i've put tha datagrid version of the code above. If you think it you can achieve it
Is there a way to delete an specific scheduled task from Windows XP/W7 ? I am trying to do that via VB.NET. The Idea is create a console app without any external DLL.
Main development XP machine died so I got a new XP machine, installed SQL Server 2005 and VS 2005 Pro, and copied my files.Projects in new VS 2005 work except the Data Sources pane won't refresh and won't show all my data sources for an existing project (from the old machine.)
Error: " An exception occurred while trying to update the data smart tasks, they will be disabled. Key not valid for use in specified state."Update: I cannot even add a new data source to a brand new project. This is VS 2005 from my MSDN subscription.
trying to automate some manual tasks. The task to access a web page (asp) login and then get some details from the site. The challenge is that the home page after login is build of 3 frames. when i see the page view source from the edit menu all i see are frame names. Once i right click on each frame and view source i am able to see the complete source - variables javascript function etc. The following code helps me to navigate :
vb.net
Set ie = CreateObject("internetexplorer.Application")
Dim s As String[code]....
After this the page has been logged in. Now to proceed further i have to click a "image" object.
1) I tried qualifying the image like ie.Document..........item("img1").click this doesn't work
2) I tried calling the javascript function directly ie.Document.all.Item("frame1").Document.parentwindow.execScript "JS_WGorUsers (funcname)", "javascript"
The 1st option gives a run time error and 2nd option says access denied. (if i login manually i am able to click the image.
