The FormatFieldMethod takes a delegate of type FormatRecordItemValue.  Basically this means that you get to define a method that will be called each time a cell is processed and you will have the opportunity to format the text.  Here's an example which just returns "hello" as the formatted text for a column.  There's no way to tell what row-index the cell is for, so you'll have to rely on the "value" parameter, and look for the string you want to format.  Alternatively, you could add a counter in the "Format" method which you could use to keep track of how many times Format was called - which should be the same as the index of the row ..