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A common class for executing tasks with a responsive UI

, 24 Jan 2009
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Execute actions while making the form wait and still be responsive to other tasks.

1.jpg

Introduction

This is a common way to implement the standard WinForms behavior of executing a potentially long running action while still having the UI be responsive and allowing the user to know that something is happening via the UI. This can be used with standard WinForms, WPF, or an MVP style application which is how I use it.

Background

Some of the other options which I felt weren't as easy as this to use:

Using the code

Download the source and hit F5 - three examples are given:

  • The standard behavior where the UI locks while executing.
  • The new behavior where the UI is not locked and the user can tell the form is busy.
  • What happens in the new behavior when an exception is thrown.

In order to use this, the form or view in question must implement the interface IThreadedExecuterView, in either the form itself or in a base form:

public partial class Form1 : Form, IThreadedExecuterView
{

#region IThreadedExecuterView Members
public void SetWait(bool isEnabled)
{
     this.Cursor = (isEnabled ? Cursors.Default : Cursors.WaitCursor);
     button1.Enabled = button2.Enabled = isEnabled;
}

public void HandleException(Exception ex)
{
     MessageBox.Show("This is your standard error " + 
                     "handling call here for " + ex.Message);
}

Below is an example of it in use - there is no need to worry about the UI thread, creating delegates, or doing anything special for exceptions other than handling them in one place.

using (ThreadedExecuter<BusinessObject> executer = 
         new ThreadedExecuter<BusinessObject>(this))
{
     executer
          .Process(() =>
          {
               return GetData(); //executes in background worker
          })
          .WhenFinished(businessObject =>
          {
               UseData(businessObject); //executes on UI thread
          })
     .Run();
}

It works for value types or reference types. Here is a Unit Test demonstrating its usage:

[Test]
public void TestThreadedExecuterNormalBehavior()
{
     int result = 0;
     bool didComplete = false;
     AutoResetEvent waiter = new AutoResetEvent(false);
     IThreadedExecuterView view = 
        MockRepository.GenerateStub<IThreadedExecuterView>();
     using (ThreadedExecuter<int> worker = new ThreadedExecuter<int>(view))
     {
          worker
               .Process(()=>
               {
                    Thread.Sleep(1000);
                    return 42;
               })
               .WhenFinished(workerResult => 
               {
                    result = workerResult;
                    didComplete = true;
                    waiter.Set();
               })
          .Run();
     }

     waiter.WaitOne(2000, false);
     Assert.AreEqual(42, result);
     Assert.IsTrue(didComplete);
}

History

  • 24-Jan-2009 - Initial version.

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

About the Author

Paul B.

United States United States
I've been a software developer since 1996 and have enjoyed C# since 2003. I have a Bachelor's degree in Computer Science and for some reason, a Master's degree in Business Administration. I currently do software development contracting/consulting.

Comments and Discussions

 
GeneralThanx, Pinmemberjohn_max5-Dec-09 9:44 
GeneralHi paul Thanks PinmemberDanie de Kock27-Jul-09 21:47 
GeneralNice mechanism Pinmembercolonel72023-Jun-09 10:54 
GeneralRe: Nice mechanism PinmemberPaul B.23-Jun-09 11:10 
Questionvoid as a return type? Pinmemberuffejz22-Apr-09 22:23 
AnswerRe: void as a return type? [modified] PinmemberDanie de Kock27-Jul-09 21:46 
GeneralRe: void as a return type? Pinmemberuffejz27-Jul-09 23:04 
GeneralRe: void as a return type? PinmemberDanie de Kock27-Jul-09 23:29 
GeneralRe: void as a return type? Sorry PinmemberDanie de Kock27-Jul-09 23:33 
GeneralRe: void as a return type? Sorry Pinmemberuffejz27-Jul-09 23:40 
GeneralRe: void as a return type? Sorry PinmemberDanie de Kock27-Jul-09 23:46 
GeneralRe: void as a return type? Sorry Pinmemberuffejz27-Jul-09 23:54 
GeneralRe: void as a return type? Pinmemberuffejz27-Jul-09 23:51 
AnswerThank you PinmemberDanie de Kock27-Jul-09 23:53 
GeneralRe: Thank you Pinmemberuffejz28-Jul-09 2:30 
GeneralRe: Thank you PinmemberDanie de Kock28-Jul-09 3:43 
GeneralRe: Thank you Pinmemberuffejz28-Jul-09 4:11 
GeneralRe: Thank you PinmemberDanie de Kock28-Jul-09 4:35 
GeneralRe: Thank you Pinmemberuffejz28-Jul-09 12:17 
GeneralRe: Thank you PinmemberDanie de Kock28-Jul-09 20:27 
Generalgood class PinmemberDonsw19-Feb-09 14:52 
GeneralKill thread Pinmembermgrounds11-Feb-09 4:35 
GeneralRe: Kill thread Pinmembermgrounds11-Feb-09 23:07 
GeneralRe: Kill thread Pinmembermgrounds12-Feb-09 5:54 
GeneralRe: Kill thread PinmemberPaul B.14-Feb-09 3:10 
GeneralRe: Kill thread Pinmembermgrounds15-Feb-09 23:47 
GeneralRe: Kill thread PinmemberPaul B.16-Feb-09 4:39 
GeneralRe: Kill thread Pinmemberuffejz22-Apr-09 22:35 
GeneralRe: Kill thread PinmemberDanie de Kock28-Jul-09 23:06 
GeneralRe: Kill thread PinmemberDanie de Kock28-Jul-09 23:24 
GeneralUnit Test Code Fails PinmemberHenrik Jonsson27-Jan-09 9:06 
GeneralRe: Unit Test Code Fails PinmemberPaul B.27-Jan-09 15:31 
GeneralRe: Unit Test Code Fails PinmemberHenrik Jonsson28-Jan-09 8:26 
GeneralMVP usage PinmemberPaul B.26-Jan-09 4:23 
GeneralMy vote of 2 PinmemberProJester125-Jan-09 8:03 
GeneralRe: My vote of 2 PinmemberPaul B.25-Jan-09 11:57 
GeneralRe: My vote of 2 PinmemberPaul B.25-Jan-09 12:00 
GeneralRe: My vote of 2 PinmemberJon_Boy20-May-09 9:39 
GeneralMVP Pinmemberuffejz25-Jan-09 3:04 
GeneralRe: MVP PinmemberPaul B.25-Jan-09 4:08 
GeneralRe: MVP Pinmemberuffejz25-Jan-09 6:41 
GeneralRe: MVP PinmemberPaul B.25-Jan-09 12:04 
GeneralRe: MVP Pinmemberuffejz26-Jan-09 1:20 
GeneralRe: MVP Pinmemberuffejz29-Jan-09 4:21 
GeneralRe: MVP Pinmemberuffejz19-Feb-09 0:41 
GeneralRe: MVP PinmemberPaul B.19-Feb-09 14:08 
GeneralRe: MVP Pinmemberuffejz23-Feb-09 21:52 
GeneralRe: MVP PinmemberPaul B.12-Mar-09 16:26 
GeneralRe: MVP [modified] Pinmemberuffejz15-Mar-09 1:44 
Hi Paul!
 
Thx for the input.. Smile | :)
 
I'm looking at the code just now, great!!
 
I'll get back to you when I have checked out the code a little bit more.
 
One question, you have used a more event based approach then a timer approach, does that works as good as using a timer that is polling values?
 
What I mean is, does the event execute as precise as a timer polling, the timer does always get values within a certain timeframe, but how good is the event stuff at this?
 
I’m just curious, it may even be better than the timer approach?
 
And your ServoMotorController class is the model then in the MVP?
 
modified on Sunday, March 15, 2009 7:58 AM

GeneralRe: MVP PinmemberPaul B.15-Mar-09 3:47 

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