By default, the FireFormatColumn property  is False. The FormatColumn event is fired only if the FireFormatColumn property of the Column object is True. The FormatColumn event lets the user to provide the cell's caption before it is displayed on the control's list. For instance, the FormatColumn event is useful when the column cells contains prices ( numbers ), and you want to display that column formatted as currency, like $50 instead 50. Also, it is useful to use the FormatColumn event when displaying computed cells.

The CellValue property of the cell is being shown as:

• formatted using the FormatCell property, if it is valid
• formatted using the FormatColumn property, if it is valid

In other words, all cells applies the format of the FormatColumn property, excepts the cells with the FormatCell property being set. If the cell belongs to a column with the FireFormatColumn property on True, the Value parameter of the FormatColumn event shows the newly caption for the cell to be shown.