Report object data source, when fields are calculated.

[Jolanta]

Hi,
I have a small question conc Object-DataSource for report.
I gather data for the data source. Then, I have a data model which is directly available for report (I see it in report designer).
The question is: if, in data-model I have
(pure example)
...
public int Field1 { get; set; }
public int Field2 { get { return Field1 + 1; } }
...
Does it mean - each time I use Field2 in my report, Field2 is calculated, or it is calculated once the DateSource is prepared?
(I am afraid, it is calculated each time Field2 is used)...

Jola