C#

protected override void OnKeyDown(KeyEventArgs e)
{
  if (e.KeyCode == Keys.Enter) //do your stuff
  else base.OnKeyDown(e);
}

private void textBox1_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)
{
	if (e.KeyCode == Keys.Return || e.KeyCode == Keys.Enter)
	{
		// do whatever you want here
		e.Handled = true;
	}
}

private void textBox2_Enter(object sender, System.EventArgs e)
{
	this.AcceptButton = button2;
}

private void textBox2_Leave(object sender, System.EventArgs e)
{
	this.AcceptButton = button1;
}

Debug.WriteLine(string text);

Trace.WriteLine(string text);

Console.WriteLine(string text);

Excel.Application excel = new Excel.ApplicationClass();
excel.Visible = true; // remove this line to keep excel silent
Excel._Workbook wbk2 = excel.Workbooks.Open(@"c:\mydoc.xls",true,true,true,true,true,true,true,true,true,true,true,true);

public class ButtonEx():System.Windows.Forms.Button
{
  public void CallButtonclick()
  {
    base.OnClick(EventArgs.Empty); // sorry mistake in first post :)
  }
}

private System.Windows.Forms.Button button1; //now becomes
private ButtonEx button1;

button1 = new System.Windows.Forms.Button(); //now changes to
button1 = new ButtonEx();

button1.CallButtonClick();

button1.Invoke( new MethodInvoker(button1.CallButtonClick));