How to asynchronously wait for x seconds and execute something then?

(transcribed from Ben as comment)

just use System.Windows.Forms.Timer. Set the timer for 5 seconds, and handle the Tick event. When the event fires, do the thing.

…and disable the timer (IsEnabled=false) before doing your work in oder to suppress a second.

The Tick event may be executed on another thread that cannot modify your gui, you can catch this:

private System.Windows.Forms.Timer myTimer = new System.Windows.Forms.Timer();

    private void StartAsyncTimedWork()
    {
        myTimer.Interval = 5000;
        myTimer.Tick += new EventHandler(myTimer_Tick);
        myTimer.Start();
    }

    private void myTimer_Tick(object sender, EventArgs e)
    {
        if (this.InvokeRequired)
        {
            /* Not on UI thread, reenter there... */
            this.BeginInvoke(new EventHandler(myTimer_Tick), sender, e);
        }
        else
        {
            lock (myTimer)
            {
                /* only work when this is no reentry while we are already working */
                if (this.myTimer.Enabled)
                {
                    this.myTimer.Stop();
                    this.doMyDelayedWork();
                    this.myTimer.Start(); /* optionally restart for periodic work */
                }
            }
        }
    }

---

Just for completeness: with async/await, one can delay execute something very easy (one shot, never repeat the invocation):

private async Task delayedWork()
{
    await Task.Delay(5000);
    this.doMyDelayedWork();
}

//This could be a button click event handler or the like */
private void StartAsyncTimedWork()
{
    Task ignoredAwaitableResult = this.delayedWork();
}

For more, see “async and await” in MSDN.