Check pixel color until I close the program

Question

I found this code:

private void PollPixel(Point location, Color color)
{
    while(true)
    {
        var c = GetColorAt(location);

        if (c.R == color.R && c.G == color.G && c.B == color.B)
        {
            DoAction();
            return;
        }
    }
}

But I don't want that return();, I want it to work until I close the program. If I remove that return the program won't work. It will start an infinte loop. I want this program to pay attention to a pixel, then if it changes its color, DoAction will activate a macro. Then it will start paying attention again. How could I do it?

If I remove that the program won't work. It will start an infinte loop. — Guilherme Pressutto, May 02 '15 at 05:34
The program will work the way you write it not the way it wants. `while (true)` indicates that there might be an infinite loop in your program. — Hamid Pourjam, May 02 '15 at 05:36
That's the problem. I want it to run forever. I don't want it to stop. But using while(true) the program won't even open. — Guilherme Pressutto, May 02 '15 at 05:38
add `Thread.Sleep(1000)` after `if` statement, this will make the program to check condition every one second. it may miss the change of course. — Hamid Pourjam, May 02 '15 at 05:40
Didn't work :/ The program stopped responding. I want an infinite loop, but I want the program to continue running while it. — Guilherme Pressutto, May 02 '15 at 05:44
The proper way to do this in a windows forms app would be to use a timer. — Blorgbeard, May 02 '15 at 05:48
If you remove the `return`, the program will behave exactly as you are describing. It will accept a color and location, and monitor it until the condition is satisfied, then call `DoAction`, then resume monitoring until the condition is satisified again. You'll need to be more specific if this is not what you want. — Asad Saeeduddin, May 02 '15 at 06:14

score 0 · Answer 1 · edited May 23 '17 at 11:50

0

You can either use Thread.Sleep or use a Timer and add an interval for doing what you wanted. The interval is in milliseconds.

Read the following posts and decide whats the best for you:

edited May 23 '17 at 11:50

Community

1
1

answered May 02 '15 at 06:07

Amir Popovich

29,350
9
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I did it with a Timer, but I didn't use a Thread.Sleep, is it wrong? – Guilherme Pressutto May 02 '15 at 06:32

Mario The Spoon · Answer 2 · 2015-05-02T06:17:49.903

0

Try:

Task.Factory.StartNew( () => {
// your code here
});

This will create a thread for your method. Do not forget to add a Thread.Sleep(1000) (or with any other value), otherwise you will create a busy loop.

Edit: a more complete sample as per request:

private bool run = true; //set this to false when your program closes
private void StartPollPixel(Point location, Color color)
{
    Task.Factory.StartNew( () => {

       while( run )
       {
           var c = GetColorAt(location);

           if (c.R == color.R && c.G == color.G && c.B == color.B)
           {
               DoAction(); //if you manipulate the UI do not forget to Invoke()
               Thread.Sleep(1000);
           }
       }

    });

}

edited May 02 '15 at 06:17

answered May 02 '15 at 06:07

Mario The Spoon

4,799
1
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It actually solves the problem... Care to explain why not? If he wants it to run until his program closes, It needs to run in a seperate thread. – Mario The Spoon May 02 '15 at 06:09
1

The OP's problem doesn't have anything to do with threading. You can add a thread of course, to avoid locking up the UI thread, but the OP's issue concerns control flow, which you haven't addressed. You haven't even shown how they would incorporate TPL, as you're suggesting, into their code. – Asad Saeeduddin May 02 '15 at 06:12
I provided a more complete example. – Mario The Spoon May 02 '15 at 06:18

Check pixel color until I close the program

2 Answers2