how to use event handler in c# code example

Example 1: how to create event in c#

class Counter
{
    public event EventHandler ThresholdReached;

    protected virtual void OnThresholdReached(EventArgs e)
    {
        EventHandler handler = ThresholdReached;
        handler?.Invoke(this, e);
    }

    // provide remaining implementation for the class
}

Example 2: c# event

private void panel1_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e) 
{
}

private void panel1_MouseEnter(object sender, System.EventArgs e) 

private void panel1_MouseHover(object sender, System.EventArgs e) 
  
private void panel1_MouseLeave(object sender, System.EventArgs e)
  
private void panel1_MouseMove(object sender, System.Windows.Forms.MouseEventArgs e)
  
private void panel1_MouseWheel(object sender, System.Windows.Forms.MouseEventArgs e)
       
private void panel1_MouseUp(object sender, System.Windows.Forms.MouseEventArgs e) 

private void panel1_Paint(object sender, System.Windows.Forms.PaintEventArgs e) 

private void clearButton_Click(object sender, System.EventArgs e)  
  
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