Occurs when the NumericUpDown.Value property has been changed in some way.
For the NumericUpDown.ValueChanged event to occur, the NumericUpDown.Value property can be changed in code, by clicking the up or down button, or by the user entering a new value that is read by the control. The new value is read when the user hits the ENTER key or navigates away from the control. If the user enters a new value and then clicks the up or down button, the NumericUpDown.ValueChanged event will occur twice.
For more information about handling events, see Consuming Events.