The AnnoFormat property allow specification of numeric and date/time formats using enumerated values.

For numeric values, each of the enumerations specify formatting similar to that specified by the .Net System.Globalization.NumberFormatInfo, including Currency, General, Exponential, Percentage, Roundtrip and Hexadecimal. NumericManual is used in conjunction with the AnnoFormatString property to specify a custom format string.

For date/time values, each of the enumerations specify formatting similar to that specified by the .Net System.Globalization.DateTimeFormatInfo class, including combinations of long and short dates and times, and universal time representations. DateManual is used in conjunction with the AnnoFormatString property to specify a custom format string.

Reference

ChartAxis Class
ChartAxis Members