An Expression is composed of operands and operators. It may be edited in one of the following ways:
Typed inline: type the expression in the Expression property box. By using the drop-down list, you can access the variables declared so far.
Use the Expression editor: to launch this editor, simply use the drop-down in the Expression property box, or double-click the Expression property or the widget element itself.
Your module is only valid if all the expressions are also valid.
There are many functions to manipulate the type Text, but the only operand that can be used directly over text is "+", which concatenates the left operand (string) with the right operand (also a string).
You cannot use any of the numeric operators to handle the types Date, Time, and DateTime. There are specific built-in functions to handle these types.
You cannot make any calculation on the type BinaryData.
You cannot make any calculation on the type Identifier. There are specific built-in functions to handle this type.
You can only use the operators "=" and "<>" for the type Record.
You cannot make any calculations on the type Record List.
Expressions in widget properties are normally evaluated when the widget is being rendered. Exceptions are:
The expressions used in the Source
Record property of an Edit
Record widget are evaluated only when the web screen is loading,
immediately after the Screen Preparation.
Source Record is always evaluated, even when the widget is inside an If widget.
The expressions used in the Source Record and Source Record List properties of the widgets Show Record, List Records, and Table Records are evaluated in screen rendering time, when a widget runtime property is first used (e.g. an expression that uses the runtime property Length of a List Records widget) or when it is rendered.
Expression Editor | Expression Operands | Expression Operators | Built-in Functions