A simple way to use thread some slower tasks, with a callback method.

It uses the BackgroundWorker.  I found this to be the simplest way to achieve what I needed. The 2 tasks I used it for were image resize & sending E-mails – doing things over the web can be slow.

// Define a new BackgroundWorker
BackgroundWorker bw = new BackgroundWorker();

// This will be threaded
bw.DoWork += delegate(object sender, DoWorkEventArgs e)
{
    BackgroundWorkerConfig cfg = (BackgroundWorkerConfig) e.Argument;
    e.Result = cfg.myVariable.ToUpper();
};

// When the thread is complete, this runs
bw.RunWorkerCompleted += delegate(object sender, RunWorkerCompletedEventArgs e)
{
    BackgroundWorkerConfig cfg = (BackgroundWorkerConfig) e.Result;
    Console.WriteLine("Completed: " + cfg.myVariable);
};

// Start the process
bw.RunWorkerAsync(new BackgroundWorkerConfig("my string goes here"));

// A class used for sending configuration variables into the Worker
class BackgroundWorkerConfig
{
    public string myVariable;
    
    public BackgroundWorkerConfig(string myVariable) {
        this.myVariable = myVariable;
    }
}

If you don’t need to send variables in, or care about getting them out, you can remove everything related to the BackgroundWorkerConfig – ie Batch Resizing images from a pre-defined folder.

One Response to “Threading / Background tasks in C# using BackgroundWorker”

1. C# Snippets | piggeh.co.uk says:

   November 9, 2010 at 15:25

   […] Threading / Background tasks […]

   Reply