Outputting Sequential Data
You can output a sequence of elements of the same type to your report using a data band. A data band has a body that represents a template for a single element of such a sequence. While building a report, sequence elements are enumerated, and the following procedure takes place for each of the elements:
- The data band body is duplicated and appended to the report.
- The appended data band body is populated with the element’s data.
Note – A data band body can contain nested data bands.
A data band body is defined between the corresponding opening and closing foreach tags within a template as follows.
<<foreach ...>>
data_band_body
<</foreach>>
You can reference an element of the corresponding sequence in template expressions within a data band body using an iteration variable. At runtime, an iteration variable represents a sequence element for which an iteration is currently being performed. You can declare an iteration variable within the corresponding opening foreach tag.
An opening foreach tag defines a foreach statement enclosed by brackets. The following table describes elements of this statement.
| Element | Optional? | Remarks |
|---|---|---|
| Iteration Variable Type | Yes | You can specify the type of an iteration variable explicitly. This type must be known by the engine (see “Setting up Known External Types” for more information). If you do not specify the type explicitly, it is determined implicitly by the engine depending on the type of the corresponding sequence. |
| Iteration Variable Name | Yes | You can specify the name of an iteration variable to use it while accessing the variable’s members. The name must be unique within the scope of the corresponding foreach tag.If you do not specify the name, you can access the variable’s members using the contextual object member access syntax (see “Using Contextual Object Member Access” for more information). |
| “in” Keyword | No | |
| Sequence Expression | No | A sequence expression must return an Iterable implementor. |
The complete syntax of a foreach tag (including optional elements) is as follows.
<<foreach [variable_type variable_name in sequence_expression]>>
data_band_body
<</foreach>>
This section includes the following topics: