After you add Background Worker control to a form, it appears in the bottom grey area of the designer: Example: Lets make a program that counts from 0 to 200 and show the result in a textbox. Do Work For I = 0 To 200 'Telling the program to count from 0 - 200 Text Box1. Sleep(1000) End If Next End Sub Check if internet connection available in Visual Basic . NET Write Or Insert Records to Access (2007) Database Table - Visual Basic . NETAllow Numbers only in a Text Box - Visual Basic .
In this example we will add a button, a textbox, and a backgroundworker: The button will be used to send the command to Background Worker to start counting in the background. Text = I 'Telling the program to show the integer I in Text Box1 Background Worker1. Sleep(1000) stop after advancing one integer for 1 second. Text = I 'Telling the program to show the integer I in Text Box1 'Telling the program to report the progress done by the Report Progress Background Worker1. NETDownload a file from a website in Visual Basic . NETUpdate Records in Access (2007) Table - Visual Basic .
Before we do this, lets adjust the Background Worker1 properties to the following: Double click on Background Worker1 and add adjust the code the following Private Sub Background Worker1_Do Work(By Val sender As System. Report Progress(I) report the progress done by the Report Progress System. Next End Sub Start the program and click on Button1. Do Work For I = 0 To 200 'Telling the program to count from 0 - 200 If Background Worker1. Report Progress(I) 'Telling the program to stop after advancing one integer for 1 second.
Notice that the program will count to 200 in the background and show the result in the textbox. Progress Percentage End Sub Private Sub Background Worker1_Run Worker Completed(By Val sender As Object, _ By Val e As System. Run Worker Completed Event Args) _ Handles Background Worker1.
Now lets see if we want to report the progress using a Progress Bar. Adjust the Background Worker1 progress changed event to the following: Private Sub Background Worker1_Progress Changed(By Val sender As Object, _ By Val e As System. Progress Changed Event Args) _ Handles Background Worker1. Run Worker Completed Msg Box("Done") End Sub Private Sub Background Worker1_Do Work(By Val sender As System.
There are lots of factors you have to consider when creating a multi-threaded program in . Going about sharing memory directly will cause a crash without setting up everything just right.
The background worker is set up such that it has several events attached to it that you add handlers to.
Sometimes it is useful to use this control when downloading a file, or copying a paste a file if the file is too large and takes a lot of time.In this example, the user presses the button which will then show a progress counter from 0 to 100% and then displays the result of the calculation. The handler you add to this event will be run in a separate thread.After the task is done, Background Worker send the result back to the form. NET Visual Basic Tutorials Simple Login Tutorial - Visual Basic . NETDisplay Access Table Records in Data Grid View - Visual Basic . NETPlacing Controls on Form Getting User Inputs in Visual Basic . The following is an example on how to use backgroundworker. NETVisual Basic Tutorials Read (Lookup) records from Access Database - Visual Basic . NET to My Sql Database Export Data Grid View Data To Excel - Visual Basic . NETLogin Tutorial Using Access Database - Visual Basic . NETDisplaying Data in a Chart / Graph - Visual Basic .
However, a lot of this work is conveniently bundled up and abstracted away from you in a . The Background Worker does exactly as its title implies. This is great if you have some complex calculation or maybe you're connecting to a slow server from your application and it blocks the UI thread.However, the background worker is not ideal if you need constant communication between the two threads.