Expressions can be used for instrument and all its elements. An expression, which calculation result will be bound to the property, can be assigned to the majority of instrument properties The expressions are used to provide elements interaction and to assign the required instrument functionality.
The order of expressions calculation is the following: if the element state was changed, the expressions recalculation of this element as well as of all elements included in it occurs. The expression calculation result is assigned to the appropriate element properties.
In order to have all instrument element values expressions recalculated during the element state alteration, it is necessary to set the RecalculateAll property to “true”. The alteration of some properties, assigning the element appearance, doesn’t invoke expressions recalculation. For example, the alteration of such properties as Fill, Stroke doesn’t invoke expressions recalculation; therefore there is no need to apply to the values of such properties.
If the expression contains syntax, semantic errors, or the exception appears in the calculation process, the expression will be ignored.
Expressions Window for the Circle element: