The thing to take
into account is that this is a very simple few lines of code that return a single value.
Expressions return single values; in our case, the result of combinedData. We want to
use it to assign a value used in some element in our report. In the above example, we
used it in a Computed Column to set the value of that Computed Column.
Scripting and Event Handling
[ 238 ]
Using Expressions in Data Elements
Expressions don't need to be as complicated as our last example. In fact, we
commonly use Expressions to set very simple values, such as setting a Data element
to the value of our current row. Let's take a look at where the Expression is most
commonly used in the Data element. Open up the Customer Orders report that we
used in the last chapter, and double-click on the CUSTOMERNUMBER field.
Here, we have a finished report with numerous Expressions used throughout. Let's
take a look at what one of these Expressions looks like.
Chapter 10
[ 239 ]
The previous image shows us a very simple Expression that retrieves the value of
the column CUSTOMERNUMBER from the current row. dataSetRow is an array
that represents the current row in the detail band, and CUSTOMERNUMBER is a
named value that points to the column where CUSTOMERNUMBER resides. It is
also possible to use numeric offsets to reference columns.
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