# Calendar.ToFourDigitYear(Int32) Method

## Definition

``````public:
virtual int ToFourDigitYear(int year);``````
``public virtual int ToFourDigitYear (int year);``
``````abstract member ToFourDigitYear : int -> int
override this.ToFourDigitYear : int -> int``````
``Public Overridable Function ToFourDigitYear (year As Integer) As Integer``

year
Int32

Int32

#### Exceptions

`year` 超出了日历支持的范围。`year` is outside the range supported by the calendar.

## Remarks

TwoDigitYearMax 为100年范围内可由两位数年份表示的最后一年。TwoDigitYearMax is the last year in the 100-year range that can be represented by a two-digit year. 通过在该100年范围内查找两位数 `year` 的唯一匹配项来确定纪元。The century is determined by finding the sole occurrence of the two-digit `year` within that 100-year range. 例如，如果 TwoDigitYearMax 设置为2029，则100年范围是从1930到2029。For example, if TwoDigitYearMax is set to 2029, the 100-year range is from 1930 to 2029. 因此，两位数值30被解释为1930，而两位数字的值29则解释为2029。Therefore, a 2-digit value of 30 is interpreted as 1930, while a 2-digit value of 29 is interpreted as 2029.

ToFourDigitYear 支持两位数年份或四位数年份。ToFourDigitYear supports either a two-digit year or a four-digit year. 如果传递了一个两位数的年份值（小于100），则会使方法根据表示相应世纪的 TwoDigitYearMax 值将值转换为四位值。Passing a two-digit year value (less than 100) causes the method to convert the value to a four-digit value according to the TwoDigitYearMax value representing the appropriate century. 如果应用程序提供了一个四位数的年份值，该范围在支持的日历范围内以 ToFourDigitYear，则该方法将返回实际输入值。If the application supplies a four-digit year value that is within the supported calendar range to ToFourDigitYear, the method returns the actual input value. 如果应用程序提供了一个在支持的日历范围之外的四位数值，或者如果它提供负值，则该方法将引发异常。If the application supplies a four-digit value that is outside the supported calendar range, or if it supplies a negative value, the method throws an exception.