TFlxApplyFormat.Format Property
Format string. (For example, "yyyy-mm-dd" for a date format, or "#.00" for a numeric 2 decimal format) This format string is the same you use in Excel under "Custom" format when formatting a cell, and it is documented in Excel documentation. Under "Finding out what format string to use in TFlxFormat.Format" section in UsingFlexCelAPI.pdf you can find more detailed information on how to create this string.
Syntax
Namespace: FlexCel.Core
public Boolean Format { get; set; }