When the NumericUpDown.UpButton method is called, either in code or by the click of the up button, the new value is validated and the control is updated with the new value in the appropriate format. Specifically, if UpDownBase.UserEdit is set to true, NumericUpDown.ParseEditText is called prior to validating or updating the value. The value is then validated to be between the NumericUpDown.Minimum and NumericUpDown.Maximum values and the NumericUpDown.UpdateEditText method is called.