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c#.netparallel-processing
iamnp
iamnp

Reputation: 508

C# .NET 4 Can Task provides notifications on UI thread?

I am using Task class in my app. This is NOT WPF application! The question is are there any possibilities of calling function from Task body on UI thread, like this:

var task = new Task(() => DoSmth(1));
task.Start();

public void DoSmth(int arg)
    {
        //smth
        CallNotifFuncOnUIThread(() => Notify(1));
        //smth ELSE
        CallNotifFuncOnUIThread(() => Notify(2));//notify AGAIN
        //smth ELSE
    }

public void Notify(int arg)
    {
        progressBar1.Value = arg;
    }

Or maybe there are other solutions of this problem? I know about BackgroundWorker class, but what about Tasks?

Upvotes: 0

Views: 1055

Answers (4)

semeai
semeai

Reputation: 96

With windows Form and progressBar1 component on ityou can use TPL IProgress interface for Task.

    private void Form1_Load(object sender, EventArgs e)
    {
        Progress<int> progress = new Progress<int>();
        var task = Alg(progress);
        progress.ProgressChanged += (s, i) => { UpdateProgress(i); };
        task.Start();
    }

    public void Notify(int arg)
    {
        progressBar1.Value = arg;
    }

    public static Task Alg(IProgress<int> progress)
    {
        Task t = new Task
        (
            () =>
            {
                for (int i = 0; i < 100; i++)
                {
                    Thread.Sleep(100);
                    ((IProgress<int>)progress).Report(i);
                }
            }
        );
        return t;
    }

Upvotes: 0

Nahum
Nahum

Reputation: 7197

UI is usually STA see: http://msdn.microsoft.com/en-us/library/windows/desktop/ms680112(v=vs.85).aspx

so in order to do something from none UI thread in the UI you need to inject somehow the msg into the thread see for example htis winform example:

http://weblogs.asp.net/justin_rogers/articles/126345.aspx

watever UI you are using you will need a similar system.

Upvotes: 0

Oliver
Oliver

Reputation: 45109

If you have a task you can start it on the gui thread by providing the correct scheduler:

Task.Factory.StartNew(() => DoSomethingOnGUI(), TaskScheduler.FromCurrentSynchronizationContext());

Upvotes: 1

David
David

Reputation: 16277

You can always call other methods inside your DoSth()

Dispatcher.Invoke(...);
Dispatcher.BeginInvoke(...);

You can also user Task.ContinueWith(...) to do sth after the task is finished processing ...

Upvotes: 1

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