Question

I have a aspx usercontrol with

static readonly string foo = GetFromDB();

now I am wondering what the lifetime of foo is. When does foo get it’s value. Everytime the usercontrol instance is created or only once? The reason for wanting to know is that GetFromDB might return a different value over time. If foo has the same value for a while thats fine. If it never changes untill the app domain is recreated then that isn’t.

Answer 1

When does foo get it’s value

When you first access the containing class and guaranteed to be executed only once and it will remain the same for the entire life of the AppDomain. You may check the following article on MSDN about static field initialization:

The static field variable initializers
of a class correspond to a sequence of
assignments that are executed in the
textual order in which they appear in
the class declaration. If a static
constructor (Section 10.11) exists in
the class, execution of the static
field initializers occurs immediately
prior to executing that static
constructor. Otherwise, the static
field initializers are executed at an
implementation-dependent time prior to
the first use of a static field of
that class.