Solved

An Action (callback) with parameters and return value

Posted on 2013-11-14
6
390 Views
Last Modified: 2013-11-14
Hi Experts,

How would I go about creating/using an Action (callback) with parameters and return value.

So here's what I am trying to accomplish:

I have a UI exe and a DLL that performs syncing operations in a background thread.  Every now and again the syncing thread needs input from the user.  What I am thinking about doing, is when the UI instantiates the background thread, it would pass it a function pointer/Action (pointing to one of the UI’s functions that would pop up a message box for the user).  Then from that point on, any time the syncing thread needs to interact with the user, it’ll use this callback function to interact with the user.  The user would click Yes/No and then that would be returned to the thread and the read would zig or zag based on the user’s input.  How would the Action declaration look like for this and how would the class constructor (accepting the function pointer) look like?

I am thinking something like this but I know I’m missing the return value:

(Please ignore the simplification of the thread part)

public class SyncerClass
{
     private Action<MyParameterClass> _useMessageCallback;

     public SyncerClass(Action<MyParameterClass> useMessageCallback)
     {
          _useMessageCallback = useMessageCallback;
          Thread.StartThread(WorkerThread);
     }

     WorkerThread()
     {
      while(true)
      {
                         MyParameterClass parameter = new MyParameterClass();
                         arameter.Message = “Would you like me to Zig instead of Zag?”;

                         if(_useMessageCallback(parameter) == DialogResult.Yes)
                         {
                              //Zig
                         }
                         else
                         {
                              //Zag
                         }
               }
     }
}

Thank you!
0
Comment
Question by:axnst2
  • 3
  • 3
6 Comments
 
LVL 22

Accepted Solution

by:
p_davis earned 500 total points
ID: 39648374
if you want a result you would either have to use func<T, TResult> or a delegate... i would suggest a delegate
0
 

Author Comment

by:axnst2
ID: 39648423
With func it worked!  Thanks!

Why would you prefer the delegate and what would the delegate prototype look like?
0
 

Author Comment

by:axnst2
ID: 39648428
delegate TResult MyDelegate(T)?
0
Master Your Team's Linux and Cloud Stack!

The average business loses $13.5M per year to ineffective training (per 1,000 employees). Keep ahead of the competition and combine in-person quality with online cost and flexibility by training with Linux Academy.

 
LVL 22

Expert Comment

by:p_davis
ID: 39648451
Its just a preference of mine... if func suites you, use it.
0
 
LVL 22

Expert Comment

by:p_davis
ID: 39648457
func actually is a delegate too, anyway
0
 

Author Closing Comment

by:axnst2
ID: 39648548
Thank you!

I ended up using this:

Func<UIMessageParameters, DialogResult> _displayUserMessage;
0

Featured Post

Live: Real-Time Solutions, Start Here

Receive instant 1:1 support from technology experts, using our real-time conversation and whiteboard interface. Your first 5 minutes are always free.

Question has a verified solution.

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

Introduction Hi all and welcome to my first article on Experts Exchange. A while ago, someone asked me if i could do some tutorials on object oriented programming. I decided to do them on C#. Now you may ask me, why's that? Well, one of the re…
Wouldn’t it be nice if you could test whether an element is contained in an array by using a Contains method just like the one available on List objects? Wouldn’t it be good if you could write code like this? (CODE) In .NET 3.5, this is possible…
This Micro Tutorial will teach you how to censor certain areas of your screen. The example in this video will show a little boy's face being blurred. This will be demonstrated using Adobe Premiere Pro CS6.
This tutorial gives a high-level tour of the interface of Marketo (a marketing automation tool to help businesses track and engage prospective customers and drive them to purchase). You will see the main areas including Marketing Activities, Design …

815 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

Need Help in Real-Time?

Connect with top rated Experts

13 Experts available now in Live!

Get 1:1 Help Now