?
Solved

C# async & await

Posted on 2015-01-15
4
Medium Priority
?
199 Views
Last Modified: 2015-01-18
Hi Experts,

I want to enumerate files in a folder and then process each file.  Normally I would have done this by creating a thread and updating the UI after each file was processed with the result.

Now I want to do this in an async and await style... I'm a bit stuck with code that looks a bit like this:

        public async void ProcessActions()
        {
            while (!m_bAllActionsProcessed)
                await Task.Run(() => ProcessNextAction());
        }

        private async Task ProcessNextAction()
        {
            if (m_nCurrentAction >= m_Actions.Count)
            {
                m_bAllActionsProcessed = true;
                return; // done.
            }

            Action<object> action = (object obj) =>
            {
                DirectoryAction directoryAction = m_Actions[m_nCurrentAction];
                DirectoryInfo info = new DirectoryInfo(directoryAction.GetDirectory());
                FileInfo[] files = info.GetFiles("*", directoryAction.GetRecurse() ? SearchOption.AllDirectories : SearchOption.TopDirectoryOnly);
                foreach (FileInfo fileInfo in files)
                    HandleFile(fileInfo);
            };

            // and now -->  also, how do I run this task??

Open in new window


Thanks!
Mike
0
Comment
Question by:thready
  • 2
4 Comments
 
LVL 1

Author Comment

by:thready
ID: 40552754
Somehow I think I'm better off on this one using good old threads....
0
 
LVL 75

Accepted Solution

by:
käµfm³d   👽 earned 1000 total points
ID: 40552864
First, you should check out the Channel 9 videos on async/await.

Second, as you'll find out in the videos, you should not be using async void for anything other than an event handler.

Third, async/await is good for I/O-bound operations, not CPU-bound operations. The reading of the files from disk is a good candidate for async/await; the processing of the files depends on what you mean by "processing" as to whether or not async/await makes sense.
0
 
LVL 86

Assisted Solution

by:Mike Tomlinson
Mike Tomlinson earned 1000 total points
ID: 40552886
Not sure how things are getting fired off...or how your boolean and "m_nCurrentAction" variable are getting changed,  but try something like this out:
        private async void button1_Click(object sender, EventArgs e)
        {
            button1.Enabled = false;

            while (!m_bAllActionsProcessed) // <-- how is "m_bAllActionsProcessed" getting changed?...
                await Task.Run(() => ProcessNextAction());

            MessageBox.Show("Done!");
            button1.Enabled = true;
        }

        private void ProcessNextAction()
        {
            DirectoryAction directoryAction = m_Actions[m_nCurrentAction]; // <-- how is "m_nCurrentAction" getting changed?...
            DirectoryInfo info = new DirectoryInfo(directoryAction.GetDirectory());
            FileInfo[] files = info.GetFiles("*", directoryAction.GetRecurse() ? SearchOption.AllDirectories : SearchOption.TopDirectoryOnly);
            foreach (FileInfo fileInfo in files)
            {
                label1.Invoke((MethodInvoker)delegate { label1.Text = fileInfo.FullName; }); // some kind of progress update
                HandleFile(fileInfo);
            }   
        }

Open in new window

0
 
LVL 1

Author Closing Comment

by:thready
ID: 40556723
async & await are God's gift to programming.  Thanks for your help!
0

Featured Post

Efficient way to get backups off site to Azure

This user guide provides instructions on how to deploy and configure both a StoneFly Scale Out NAS Enterprise Cloud Drive virtual machine and Veeam Cloud Connect in the Microsoft Azure Cloud.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

For most people, the WrapPanel seems like a magic when they switch from WinForms to WPF. Most of us will think that the code that is used to write a control like that would be difficult. However, most of the work is done by the WPF engine, and the W…
Hello there! As a developer I have modified and refactored the unit tests which was written by fellow developers in the past. On the course, I have gone through various misconceptions and technical challenges when it comes to implementation. I would…
This is Part 3 in a 3-part series on Experts Exchange to discuss error handling in VBA code written for Excel. Part 1 of this series discussed basic error handling code using VBA. http://www.experts-exchange.com/videos/1478/Excel-Error-Handlin…
Is your OST file inaccessible, Need to transfer OST file from one computer to another? Want to convert OST file to PST? If the answer to any of the above question is yes, then look no further. With the help of Stellar OST to PST Converter, you can e…

864 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question