// This is a custom TextBox control that overrides the OnClick method
// to allow one-click selection of the text in the text box.

public class SingleClickTextBox: TextBox

{
    protected override void OnClick(EventArgs e)
    {
        this.SelectAll();
        base.OnClick(e);
    }
}

// This example uses the Parent property and the Find method of Control to set
// properties on the parent control of a Button and its Form. The example assumes
// that a Button control named button1 is located within a GroupBox control. The 
// example also assumes that the Click event of the Button control is connected to
// the event handler method defined in the example.
private void button1_Click(object sender, System.EventArgs e)
{
   // Get the control the Button control is located in. In this case a GroupBox.
   Control control = button1.Parent;
   // Set the text and backcolor of the parent control.
   control.Text = "My Groupbox";
   control.BackColor = Color.Blue;
   // Get the form that the Button control is contained within.
   Form myForm = button1.FindForm();
   // Set the text and color of the form containing the Button.
   myForm.Text = "The Form of My Control";
   myForm.BackColor = Color.Red;
}