By default, the FormatLabel property is Empty. The
FormatLabel property has effect only if it is valid and not empty. The Label
property defines the label being shown in the chart. Use the FormatLabel
property to customize the labels being displayed in the chart's level. The value
keyword in the FormatLabel property specifies the label of the level as it is
before formatting ( in string format ). The dvalue keyword, indicates
the date-time expression of the element in the label being formatted. Also,
you can use the ReplaceLabel property to
replace a specified label.

For instance, you can use the FormatLabel property to customize the
labels and the subdivisions in your chart as you can see in the following
screen shot ( "'Group <b>'+int(1 +dvalue/16)" ):

If the Unit property is exDay for several
levels ( more than 1 level ), you can display your subdivisions using the Count
property, based on 0, not based on the FirstVisibleDate property. You can get
this layout using the

Other sample would be, if you need to display the last Friday of each month using a
different color, so in this case you can use the FormatLevel property as
"(weekday(dvalue)=5 ? month(dvalue+7)!=month(dvalue) ? '<b><bgcolor=000000><fgcolor=FFFFFF>' ) +
value" as in the following screen shot:

The screen shows in different colors the Jun 27 as being the last Friday
of June, and the Jul 25 as being the last Friday on July.

The following screen shot shows the week end days using a different
foreground color ( FormatLabel property is "weekday(dvalue)=6 ? '<fgcolor=D0D0D0>Sa' : ( weekday(dvalue)=0 ? '<fgcolor=D0D0D0>Su' : value
)" )

The value
keyword in the FormatLabel property specifies the label of the level as it is
before formatting ( in string format ). The dvalue keyword, indicates
the date-time expression of the element in the label being formatted.

This property/method supports predefined constants and operators/functions as described here.

The following VB sample shows how you can highlight the last Friday for each month::