Use IProgress to implement asynchronous programming process notifications, and iprogress Asynchronously

Use IProgress to implement asynchronous programming process notifications, and iprogress Asynchronously

 

In asynchronous programming, you can use IProgress <in T> to display the progress.

 

IProgress <in T> only provides the void Report (T value) method. The Report method reports a value of the T type to IProgress, then, the constructor of the IProgress <in T> Implementation class Progress <in T> receives the form parameters of the Action <T> type, and displays the Progress in the UI through this delegate.

 

First, write a method to Report the progress using the Report method.

 

        public void DoProcessing(IProgress<int> progress)
        {
            for (int i = 0; i != 100; ++i)
            {
                Thread.Sleep(100);
                if (progress != null)
                {
                    progress.Report(i);
                }
            }
        }

 

How can I display the progress in the UI?

 

Implements the IProgress <in T> interface Progress <int T> class, receives an Action <T>, and displays the Progress to the UI through this delegate.

 

        private async void button1_Click(object sender, EventArgs e)
        {
// Current thread
            var progress = new Progress<int>(percent => { label1.Text = percent + "%"; });
// Thread pool thread
            await Task.Run(() => DoProcessing(progress));
Label1.Text = "end ";
        }

 

For example, You Need To asynchronously read a remote file.

 

public async Task DownloadFileAsync(string fileName, IProgress<int> progress)
{
    using(var fileStream...)
    {
        using(var ftpStream = ...)
        {    
            while(true)
            {
// Asynchronously reads data
                var bytesRead = await ftpStream.ReadAsync(...);
                if(bytesRead == 0)
                {
                    return;
                }
// Write data Asynchronously
                await fileStream.WriteAsync(...);
                if(progress != null)
                {
                    progress.Report(bytesRead);
                }
            }
        }
    }
}