property ConditionalFormat.Valid as Boolean
Checks whether the expression is syntactically correct.

TypeDescription
Boolean A boolean expression that indicates whether the Expression property is valid.
Use the Valid property to check whether the Expression formula is valid. The conditional format is not applied to objects if expression is not valid, or the Enabled property is false. An empty expression is not valid. Use the Enabled property to disable applying the format to columns or items. Use the Remove method to remove an expression from ConditionalFormats collection. The Verify property checks whether the current conditional expression is applied to the giving item.