How to provide a feedback to UI in a async method?

Question

I have been developing a windows forms project where I have a 10 tasks to do, and I would like to do this in a async way. These tasks will star when the user cl

Answer 1

Sriram covered how to do the async/await in his answer, however I wanted to show you another way to update the progress on the UI thread using his answer as a base.

.NET 4.5 added the IProgress interface and the Progress class. The built in Progress class captures the synchronization context, just like async/await does, then when you go to report your progress it uses that context to make its callback (the UI thread in your case).

private async void button1_Click(object sender, EventArgs e)
{
     var progress = new Progress(UpdateRow); //This makes a callback to UpdateRow when progress is reported.

     var tasks = Processes.Select(process => ProcessObject(process, progress)).ToList();
     await Task.WhenAll(tasks);
}

private async Task ProcessObject(ProcessViewModel process, IProgress progress)
{
    // my code is here with some loops
    await Task.Run(()=>
    {
        //Will be run in ThreadPool thread
        //Do whatever cpu bound work here


        //Still in the thread pool thread
        process.Progress++;

        // feedback to UI, calls UpdateRow on the UI thread.
        progress.Report(process); 
    });
}