Understanding the report life cycle, what happens and when it happens
is crucial to effectively using Telerik Reporting.
The diagram shown below describes the sequence of stages from
designer to completed document.
The section "Report Lifecycle Overview" below provides further
detail on the activities that occur at each stage of the report lifecycle.
The section "Report Processing Flow" explains
what report sections may contain - data items, data bound fields, aggregates and
The section "Report Rendering Flow" explains
what page sections may contain.
Report Life Cycle Overview
The report is designed in a Report Designer. The act of designing the report produces a report definition
that based on the used designer is:
The report is processed:
Performs all grouping, sorting and filtering
Evaluates all Expressions except page header and
footer section items.
Binds the Report Definition and nested Data Items with data from the
available data sources.
Triggers item Binding event, item Bindings and item Bound events.
Produces a Processing Report. The Processing Report is cached so it can be used
for print and export operations.
The report is rendered:
The Processing Report is passed to a specific
rendering extension (e.g. MHTML or PDF output formats).
The Processing Report is paged if the output
format supports paging.
Item expressions are evaluated in the page
header and footer sections for every page.
The report is rendered to the Output Document.
Report Processing Flow
There are many ramifications of the report lifecycle including when you can use bound data fields, aggregates and page
information functions across the Data Items.
Report Header and Footer sections:
Item binding expressions should use only aggregate functions. If
an expression specifies a data field without an aggregate, the
First() aggregate function is used by
default. The First() function returns the
first record of the data source for the specified field.
Detail Section: The detail
section item binding expressions can contain data bound fields,
except PageCount and PageNumber.
Report Group sections: Item binding expressions
should only use Aggregate Functions.
If an expression specifies a data field without an aggregate, the First()
aggregate function is used by default. The First()
function returns the first record of the group data members for the specified
The processing stages of a report apply to Data Items (Table, CrossTab, List, Chart, SubReport) nested inside report sections as well, meaning all operations performed
on a processing report are performed to all Data Items in report sections.
Report Rendering Flow
Page Header and Footer sections:
Item binding expressions cannot use data fields or aggregate
functions. Paging is specific to rendering format and must occur
during rendering, well after early report processing where data
binding occurs. PageNumber and
PageCount global objects are available
only in this section.