Question

I have created a new Windows Forms Application with C# and .NET 4.0, and I have a function that must be called automatically every 60th of a second. My problem, is that I do not know where to call this function. .NET forms don’t appear to have a built-in on-update event.

How would I go about getting this function called every 60th of a second?
Sorry if it is a beginner question.

Answer 1

You could set up a Timer to invoke a callback every 16 ms (which is 1/60 sec).

Important point as mentioned by @spender: If you are requiring very precise timing on this, eg exactly every 1/60 sec precision, you will not be satisfied with this solution. Windows does not natively do high-resolution timing in that vein very well. Props to @spender for the mention.

Here’s a sample class with a rough outline of how it might look in a plain vanilla class, so you’d need to adapt it to your form:

You might also want to call this on a background thread, but if you’re new to WinForms, we’ll start in small chunks. Let’s try the timer first, then go from there.

class Demo{

   System.Timers.Timer myTimer;

   void InitializeTimer(){
      myTimer = new Timer(16); // elaps every 1/60 sec , appx 16 ms.
      myTimer.ElapsedEventHandler+=new ElapsedEventHandler(myTimerEventHandler); //define a handler
      myTimer.Enabled=true; //enable the timer.
   }

   void myTimerEventHandler(object sender, ElapsedEventArgs e){
     // do your thing here
   }
}

EDIT: Extra demo code for background thread creation and Invoked-based GUI update

As noted in my comment below, this is not as polished as I would like it, but I think it illustrates the salient points. It defines a BackgroundWorker thread to move the thread invocations to the background; the thread callback checks for the need to call Invoke, and calls right back to itself across a delegate invocation to allow for the custom form update in the “else” block of the “if (InvokeRequired)” statement. In a nutshell, a background thread starts, and starts a timer; when the timer elapses, it calls the updater on the background thread, which checks to see if Invoke must be called, and if it is, performs the thread context switch back to the GUI thread through the recall to the method, which then performs the GUI update. Put your custom update code in that “else” block. I hope this helps!!!

public partial class Form1 : Form
{
    delegate void FormUpdateDelegate(object sender, ElapsedEventArgs e);
    public BackgroundWorker backgroundThread; 
    System.Timers.Timer foo;
    Random colorgen = new Random();
    public Form1()
    {
        InitializeComponent();

        backgroundThread = new BackgroundWorker();
        backgroundThread.DoWork+=new DoWorkEventHandler(backgroundThread_DoWork);
        backgroundThread.RunWorkerAsync();
    }

    public void formUpdater(object sender, ElapsedEventArgs e)
    {
        if (InvokeRequired)
        {
            FormUpdateDelegate d = new FormUpdateDelegate(formUpdater);
            Invoke(d, new object[] { sender, e });
        }
        else
        {
            // Do your form update here
            this.label1.ForeColor = Color.FromArgb(colorgen.Next());
        }
    }

    public void backgroundThread_DoWork(object sender, DoWorkEventArgs e)
    {
        foo = new System.Timers.Timer(16);
        foo.Elapsed += new ElapsedEventHandler(formUpdater);
        foo.Start();
    }

}