Background Worker Overview with Example in Winforms - Part 1

Recently, while working on Winform Application, we require certain time consuming tasks on Form load to run in separate Thread. We decided to use Background Worker Component in our application. However, there is need that Background Component will be used in multiple forms. So I decided to create a class which inherits from BackgroundWorker Class and implemented certain common functionality over there. I like to share the code and overview of Background worker class.

BackgroundWorker Component Overview:

The BackgroundWorker class allows you to run an operation on a separate, dedicated thread. Time-consuming operations like

•     Image downloads
•     Web service invocations
•     File downloads and uploads (including for peer-to-peer applications)
•     Complex local computations
•     Database transactions
•     Local disk access

can cause your user interface to hang while they are running. When you want a responsive UI and you are faced with long delays associated with such operations, the BackgroundWorker component provides a convenient solution.

The BackgroundWorker component gives you the ability to execute time-consuming operations asynchronously ("in the background"), on a thread different from your application's main UI thread.

To use a BackgroundWorker, you simply tell it what time-consuming worker method to execute in the background, and then you call the RunWorkerAsync method. Your calling thread continues to run normally while the worker method runs asynchronously. When the method is finished, the BackgroundWorker alerts the calling thread by firing the RunWorkerCompleted event, which optionally contains the results of the operation.

The BackgroundWorker component is available from the Toolbox, in the Components tab. To add a BackgroundWorker to your form, drag the BackgroundWorker component onto your form. It appears in the component tray, and its properties appear in the Properties window.

By using a pattern of method calls (RunWorkerAsync, ReportProgress) and event callbacks (DoWork, ProgressChanged, RunWorkerCompleted), BackgroundWorker helps you easily create a background thread and factor out the stuff that should be running on the background thread versus the foreground thread. 

If your background operation requires a parameter, call RunWorkerAsync with your parameter. Inside the DoWork event handler, you can extract the parameter from the DoWorkEventArgs.Argument property. 

Below image shows the flow of working of Background Worker model.

Above is the brief overview of how Background worker class works and what are its key events and methods. In the next article [Background worker example - Filling dataset in separate thread - Part 2], I explained working of Background worker class with code, which fills the Dataset in background and also shows the progress-bar while running the process in background.