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Dynamic Properties

When you use RADpage, the properties of all components remain static constants. With heitml programming, however, you can pass dynamically calculated values to components. So, for example:

<display value="Test">

prints just 'Test' but

<display value=20*70>

evaluates the expression and prints 1400. heitml programming, therefore, allows you to dynamically adapt the properties of all components. (See the Programming section for details about heitml expressions and programs.)

A more practical example, perhaps, is:

<display value=right(SrvHost,".")>

It displays the top level domain of the client computer. The variable SrvHost contains the fully qualified domain name of the client, for example 10.1.0.0. The right() function call returns the text from SrvHost that follows the rightmost ".", '0' in this case.

Another example is a daily counter:

You are guest number <Counter name="gt"+SrvDate>

Here we have an ordinary page counter, but the name of the counter is gt followed by the current date. This means that a new counter will be created every day to track all page accesses that occur on that day. For example, today we use the counter gt20210618 and its current value is .

When using these features, make sure that you always use the Source button of the RADpage window to edit components with dynamic properties.

<cond show>This text is shown.</cond>

could be modified as follows:

<cond show=SrvTime<120000000 >This text is shown in the morning.</cond>

A more advanced example of dynamic properties is to use them to build up database queries. The value parameter of a dbconstrain can be an expression rather than a constant. The tutorial contains an example of two nested dbdisplay components. The outer one select all possible countries. The inner one then select all the guests coming from the current country. The dbconstrain of the inner query uses the expression panelfield(1).Country to access the country field of the enclosing query.

Reference

Component:displayDetails
A value is displayed. This especially makes sense, if a dynamically computed value condition is used, which is possible programming .
Property Kind Description
ValueString(10) Value to be shown. 
FormatString(10) Formatting 
LayoutString(10) Layout 


This page was dynamically generated by the web application development tool RADpage of H.E.I. Try the AJAX Article (in German) on www.h-e-i.de.
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