Working with Table-Row Data Bands

A table-row data band is a data band which body occupies single or multiple rows of a single document table. The body of such a band starts at the beginning of the first occupied row and ends at the end of the last occupied row as follows.

<<foreach ...>> ...	...	...
...	...	...
...	...	... <</foreach>>

The following examples in this section are given using ds, a DataSet instance containing DataTable and DataRelation objects according to the following data model.

The most common use case of a table-row data band is the building of a document table that represents a list of items. You can use a template like the following one to achieve this.

Client	Manager	Contract Price
<<foreach [c in ds.Contracts]>><<[c.Clients.Name]>>	<<[c.Managers.Name]>>	<<[c.Price]>><</foreach>>
Total:		<<[ds.Contracts.sum(c => c.Price)]>>

In this case, the engine produces a report as follows.

Client	Manager	Contract Price
A Company	John Smith	1200000
B Ltd.	John Smith	750000
C & D	John Smith	350000
E Corp.	Tony Anderson	650000
F & Partners	Tony Anderson	550000
G & Co.	July James	350000
H Group	July James	250000
I & Sons	July James	100000
J Ent.	July James	100000
Total:		4300000

To populate a document table with a master-detail data, you can use nested table-row data bands like in the following template.

Manager/Client	Contract Price
<<foreach [m in ds.Managers]>><<[m.Name]>>	<<[m.Contracts.sum(c => c.Price)]>>
<<foreach [c in m.Contracts]>> <<[c.Clients.Name]>>	<<[c.Price]>><</foreach>><</foreach>>
Total:	<<[ds.Contracts.sum(c =>c.Price)]>>

In this case, the engine produces a report as follows.

Manager/Client	Contract Price
John Smith	2300000
A Company	1200000
B Ltd.	750000
C & D	350000
Tony Anderson	1200000
E Corp.	650000
F & Partners	550000
July James	800000
G & Co.	350000
H Group	250000
I & Sons	100000
J Ent.	100000
Total:	4300000

You can normally use common data bands nested to table-row data bands as well like in the following template.

Manager	Client
<<foreach [m in ds.Managers]>><<[m.Name]>>	<<foreach [c in m.Contracts]>><<[c.Clients.Name]>><</foreach>><</foreach>>

In this case, the engine produces a report as follows.

Manager	Clients
John Smith	A Company B Ltd. C & D
Tony Anderson	E Corp. F & Partners
July James	G & Co. H Group I & Sons J Ent.

Note – Table-column data bands can also be nested to table-row data bands (see “Working with Cross (Pivot) Tables” for details), but not conversely: Nesting of table-row data bands into table-column data bands is forbidden.

A special case is a data band inside a single-column table row. In such a case, if you put opening and closing foreach tags in the same cell, the engine treats a data band formed by these tags as a common one rather than a table-row one by default. The following template illustrates such a scenario.

Managers
<<foreach [m in ds.Managers]>><<[m.Name]>> <</foreach>>

In this case, the engine produces a report as follows.

Managers
John Smith Tony Anderson July James

However, if needed, you can override this behavior making the engine to treat such a data band as a table-row one by specifying a greedy switch like in the following template.

Managers
<<foreach [m in ds.Managers]>><<[m.Name]>><</foreach -greedy>>

In this case, the engine produces a report as follows.

Managers
John Smith
Tony Anderson
July James

For more examples of templates for typical scenarios involving table‑row data bands, see “Appendix C. Typical Templates”.

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FAQ

1. Q: How can I force a data band that has its opening and closing foreach tags in the same cell to be treated as a table‑row data band?
   A: Add the -greedy switch to the closing tag. Example: <<foreach [m in ds.Managers]>>...<< /foreach -greedy>>. The greedy switch tells the engine to treat the band as a table‑row band even when the tags are in a single cell.

2. Q: Is it possible to nest common (row‑independent) data bands inside a table‑row data band?
   A: Yes. You can place any common data band (e.g., a foreach that outputs a list of values) inside the body of a table‑row data band. The outer table‑row band controls the rows, while the inner common band repeats its content within a single cell.

3. Q: How do I calculate a sum of a numeric column inside a table‑row data band?
   A: Use a LINQ expression inside a tag, for example <<[ds.Contracts.sum(c => c.Price)]>>. The expression is evaluated once for the whole data set and the result is inserted into the cell.

4. Q: What is the correct way to create a master‑detail report using nested table‑row data bands?
   A: Place an outer foreach that iterates over the master collection (e.g., managers) and inside its row add another foreach that iterates over the related detail collection (e.g., contracts). Example:

   <<foreach [m in ds.Managers]>> <<[m.Name]>>
   <<foreach [c in m.Contracts]>> <<[c.Clients.Name]>> <<[c.Price]>> <</foreach>>
   <</foreach>>
   

   This produces a row for each manager and rows for each of their contracts.

5. Q: Can I nest a table‑row data band inside a table‑column data band?
   A: No. Nesting a table‑row data band into a table‑column data band is forbidden. A table‑row data band can contain common data bands, other table‑row data bands (for master‑detail data), and table‑column data bands.