imho, answers to date have missed a fundamental issue: the critical Event to use to discriminate a 3-second interval where the Mouse is over a Control is MouseEnter, not MouseHover.
1. at design-time:
a. put a Button Control on the Form, 'button1: wire up its MouseEnter, and MouseLeave EventHandlers as shown below.
b. put a TextBox Control on the Form, 'textBox1: set its MultiLine property to 'true. Set its ScrollBar property to 'Vertical.
c. put a Timer Component on the Form, 'timer1: wire up its Tick EventHandler as shown below.
2. The code:
private bool overTheButton;
private bool hoverOverTheButtonEventTriggered = false;
private void button1_MouseEnter(object sender, EventArgs e)
{
overTheButton = true;
hoverOverTheButtonEventTriggered = false;
timer1.Start();
}
private void button1_MouseLeave(object sender, EventArgs e)
{
overTheButton = false;
hoverOverTheButtonEventTriggered = false;
timer1.Stop();
}
private void button1_Click(object sender, EventArgs e)
{
if (hoverOverTheButtonEventTriggered)
{
textBox1.Text += "3 second hover event triggered" + Environment.NewLine;
hoverOverTheButtonEventTriggered = false;
}
else
{
textBox1.Text += "Regular click" + Environment.NewLine;
timer1.Stop();
}
}
private void timer1_Tick(object sender, EventArgs e)
{
timer1.Stop();
if (overTheButton && ! hoverOverTheButtonEventTriggered)
{
hoverOverTheButtonEventTriggered = true;
button1.PerformClick();
}
}
3. Run the code: observe what happens if you click the Button before the Mouse has been over the Button 3 seconds. Observe what happens if you click the Button before three-seconds of having the Mouse over it, and don't move the Mouse (it remains over the Button). Observe what happens if you move the Mouse over the Button for three seconds and leave the Mouse over the Button after the first 3-second Click occurs ... and so forth.
4. Note the assumptions made here:
a. the programmer wants to do one thing if the Button gets a Click because the Timer elapsed, and, possibly, another, if the Button is clicked before the Timer elapses.
b. in the case the user leaves the Mouse over the Button, and a Timer-elapsed Click event is triggered: the programmer does not want to start the Timer again just because the Mouse remains over the Button.
c. in the case the user clicks on the Button before three-seconds of having the Mouse over it: the programmer doesn't want a Timer based event to be triggered just because the Mouse stays over the Button.
~
If your use-case doesn't make the same assumptions: please, change this code :)