/// <summary>
/// Constructs an instance of <see cref="Month"/> from integer year and month numbers.
/// </summary>
/// <param name="year">The number of the year being constructed. Must be in the inclusive range 1 to 9998.</param>
/// <param name="month">The number of the month of the year for the month being constructed, with 1 representing
/// January, 2 February etc.</param>
/// <exception cref="ArgumentOutOfRangeException">Either the year or month parameters is outside of the range of permissible
/// years or months respectively.</exception>
public Month(int year, int month)
{
Preconditions.CheckArgumentOutOfRange(nameof(year), year, Constants.MinCalendarYearNum, Constants.MaxCalendarYearNum);
Preconditions.CheckArgumentOutOfRange(nameof(month), month, 1, 12);
_value = (year - 1) * 12 + month - 1;
}
/// <summary>
/// Constructs an instance of <see cref="Month"/> by directly setting the private integer _value field.
/// </summary>
/// <param name="value">Integer value to assign to private _value field.</param>
private Month(int value)
{
Preconditions.CheckArgumentOutOfRange(nameof(value), value, MinValue, MaxValue);
_value = value;
}
/// <inheritdoc/>
void IXmlSerializable.WriteXml(XmlWriter writer)
{
Preconditions.CheckParameterNotNull(writer, nameof(writer));
writer.WriteString(ToString());
}