The Expression property indicates the format to be displayed instead the value itself. If the Expression is not valid, the FormatContent object shows as disabled in the control's context menu. The Visible property shows or hides the current FormatContent object within the column's drop down content menu. The Name property specifies the HTML caption to be displayed on the control's context menu. The ToolTip property specifies the HTML tooltip to be displayed on the control's context menu, when the cursor hovers the object. For instance, you can use the Expression to display a computed column. 

For instance: 

• "len(value) ? (value format '') : ''", displays the value in numeric format, if it is not empty
• "len(value) ? currency(value) :''", displays the value in currency format, if it is not empty
• "upper(value)", displays the value in upper-case
• "%2 + %3/%4" adds the value of the third generated column to the result of dividing the fourth column by the fifth generated column (computed column)

The value keyword in the Expression property indicates the value/result to be converted.

The expression supports cell's identifiers as follows:

• %0, %1, %2, ... specifies the value of the cell in the column with the index 0, 1 2, ...

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