Question

I have several process that need to run in the background of a Windows Forms application, because they take too much time and I do not want to freeze the user interface until they completely finish, I would like to have an indicator to show the process of each operation, so far I have a form to show the progress of each operation but my operations run synchronously.

So my question is what is the easiest way to run these operation (that access the database) async??

I forgot one important feature that the application requires, the user will have the option to cancel any operation at any time. I think this requirement complicates the application a lot, at least with my current skills, so basically I would like to enphatize that I need a solution easy to understand, and easy to implement. i am aware there will be good practices to follow but at this point I would like some code working later I with more time I would refactor the code

Answer 1

Well in C# there are several ways to accomplish this

Personally I would recommend you to try the Reactive Extensions

http://msdn.microsoft.com/en-us/data/gg577609.aspx

You can actually do something like this:

https://stackoverflow.com/a/10804404/1268570

I created this for you, this is really easy although it is not thread-safe but this would be a good start point

In a form

var a = Observable.Start(() => Thread.Sleep(8000)).StartAsync(CancellationToken.None);
var b = Observable.Start(() => Thread.Sleep(15000)).StartAsync(CancellationToken.None);
var c = Observable.Start(() => Thread.Sleep(3000)).StartAsync(CancellationToken.None);

Manager.Add("a", a.ObserveOn(this).Subscribe(x => MessageBox.Show("a done")));
Manager.Add("b", b.ObserveOn(this).Subscribe(x => MessageBox.Show("b done")));
Manager.Add("c", c.ObserveOn(this).Subscribe(x => MessageBox.Show("c done")));

private void button1_Click(object sender, EventArgs e)
{
    Manager.Cancel("b");
}

Manager utility

public static class Manager
{
    private static IDictionary<string, IDisposable> runningOperations;

    static Manager()
    {
        runningOperations = new Dictionary<string, IDisposable>();
    }

    public static void Add(string key, IDisposable runningOperation)
    {
        if (runningOperations.ContainsKey(key))
        {
            throw new ArgumentOutOfRangeException("key");
        }

        runningOperations.Add(key, runningOperation);
    }

    public static void Cancel(string key)
    {
        IDisposable value = null;
        if (runningOperations.TryGetValue(key, out value))
        {
            value.Dispose();
            runningOperations.Remove(key);
        }
    }