CODEWITHSUNDEEP
c#.net-3.5
user1984300
user1984300

Reputation: 99

Wait for maximum 5 seconds

I am trying to implement something that waits for a boolean to be true. If after 5 seconds the boolean is still not true then i will execute the error message code

This is what I am doing now. But this method just waits for 5 seconds for all cases, which is wasting time. How can I do something like that this that executes as soon as the variable becomes true?

Thread.Sleep(5000);
if (imageDisplayed == true) {
    //success
}
else {
    //failed
}

Upvotes: 0

Views: 6195

Answers (5)

Rufus L
Rufus L

Reputation: 37060

You can set a timeout variable to the time that you want to stop waiting and use that, along with the check that you're waiting for, as a condition in a while loop. In the example below, we just sleep for a tenth of a second between checks, but you can adjust the sleep time (or remove it) as you see fit:

var timeout = DateTime.Now.AddSeconds(5);

while (!imageDisplayed && DateTime.Now < timeout)
{
    Thread.Sleep(100);
}

// Here, either the imageDisplayed bool has been set to true, or we've waited 5 seconds

Upvotes: 1

bastijn
bastijn

Reputation: 5953

Better to use a ManualResetEvent for this.

// Somewhere instantiate this as an accessible variable to both 
// display logic and waiting logic.
ManualResetEvent resetEvent = new ManualResetEvent(false);

// In your thread where you want to wait for max 5 secs
if(resetEvent.WaitOne(5000)) {   // this will wait for max 5 secs before continuing.
    // do your thing
} else {
    // run your else logic.
}

// in your thread where you set a boolean to true
public void DisplayImage() {
    // display image
    display();

    // Notify the threads waiting for this to happen
    resetEvent.Set();   // This will release the wait/lock above, even when waiting. 
}

Rule of thumb. Better not use sleeps in your production code unless you have a really, really, really good reason to do so.

Upvotes: 4

AviatorBlue
AviatorBlue

Reputation: 1

Sounds like you want to use the System.Timers.Timer class.

Setup your boolean variable to execute a function when it is set to true

    System.Timers.Timer t;
    private bool val;
    public bool Val {
        get { return val; }
        set
        {
            if (value == true)
                // run function here
            val = value;
        }
    }

Then Setup your timers interval for every 5 seconds.

    public Main()
    {
        InitializeComponent();

        t = new System.Timers.Timer(5000);

        t.Elapsed += T_Elapsed;
    }

    private void T_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
    {
        throw new Exception();
    }

To start the timer simply use t.Start() and t.Reset() to reset the timer

Upvotes: -2

Kolichikov
Kolichikov

Reputation: 3020

Use a while loop and checking incrementally for your condition

var waitedSoFar = 0;
var imageDisplayed = CheckIfImageIsDisplayed(); //this function is where you check the condition

while(waitedSoFar < 5000)
{
   imageDisplayed = CheckIfImageIsDisplayed();
   if(imageDisplayed)
   {
      //success here
      break;
   }
   waitedSoFar += 100;
   Thread.Sleep(100);
}
if(!imageDisplayed)
{
    //failed, do something here about that.
}

Upvotes: 0

TomServo
TomServo

Reputation: 7409

Break your sleeps up into "naps." ;)

for (int n = 0; n < 50; n++)
{
    Thread.Sleep(100);
    if (imageDisplayed)
    {
        // success
        break;
    }
}
//failed

Not quite instantly, but with a maximum 100ms latency.

Upvotes: 0

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