Dave wrote:
Hi,
Is there a general rule to use 'static' on a class member? It seems
uneccessary to have to create an instance of an object just to use it's
methods where declaring something as static makes more sense.
Instance methods are instance methods because they rely on the state of
the specific object instance. Instance methods are tied to a particular
instance because the behavior that the method invokes relies upon the
state of that particular instance.
When you declare a method as static, you define that method as being a
class method. A class method applies to the class as opposed to any
particular instance. The behavior instigated by a class method does not
rely on the state of a particular instance. In fact, a static method
cannot rely on an instance's state since static methods lack access to
this reference. Instead, the behavior of a class method either depends
on a state that all objects share at the class level, or is independent
of any state at all.
If a method relies on an object instance's state it should be an
instance methods. If a method is general for all or no instances of a
class, and does not rely on the object state, it should be a static method.
Instance methods are most commonly used. However static methods are very
useful for utility and factory classes amogst many other uses.
Anders Norås
http://dotnetjunkies.com/weblog/anoras/ 
