Print a Layout-dependent reference (InfoNodes)

InfoNodes allow you to print a value on the report that depends on the paged stream resulting from the report layout. For example, a value for "total from previous page" can vary depending on how the page options for a report are set. In order to have a report layout that will work with various page sizes, you can use an InfoNode and a Reference Box.

This example illustrates how to print the total price (overalltotal) from a previous page:

First, the REPORT block of the BDL file associated with the report must calculate the desired value and output it to the report. The following example is from the OrderReport.4gl file in the demo sample programs:
```
ON EVERY ROW
 LET lineitemprice = orderline.lineitem.unitprice * orderline.lineitem.quantity 
 LET overalltotal = overalltotal + lineitemprice 
 LET ordertotal = ordertotal + lineitemprice 
 PRINT orderline.*, lineitemprice, overalltotal, ordertotal
```
The variable overalltotal contains the running total price of the lineitems on the report.
You will use these objects from the Toolbox in your report design:
- InfoNode - place this object in the container for the ON EVERY ROW trigger of your Structure view. This will create an invisible column in your report line containing the value of the InfoNode.
  The Value property of the InfoNode must be a String. You can use the fglValue member of the FGLNumericVariable class to convert overalltotal:
```
 overalltotal.fglValue
```
  This will format the value of overalltotal as a String based on the default format set in the Genero DVM. Or, you can use the format method of the Numeric class to convert to a string and also specify the format, as in this example:
```
 overalltotal.format("-,---,---,--&.&&") 
```
- Reference Box - place this object in the Page Header at the top of the report structure.
  - For the InfoNode name property, enter the name of the InfoNode that you created.
  - For the text property, enter a string that will only be used to determine the maximum length of the value in the InfoNode, since the value will not be known at the time the ReferenceBox is positioned. Examples: Enter "000,000.00" as the maximum length for a value that is from a numeric data type, or "MMMM" as the maximum length for a value that is from a CHAR(4) data type.
- WordBox - optionally use this object to add some text next to the Reference Box.
A Reference Box points to the immediately previous occurrence of the InfoNode value in the paged stream. Because you placed the Reference Box in a Page Header, it will point to the last occurrence of the overalltotal value on the previous page.