Question

Possible Duplicate:
Properties vs Methods

In method you can type some code and in properties too. For example I have a property Name. When class name changes I would like to get some data from database and change state of my object. I can add this code to set part of my property. Other solution is to change set part to private and add method called SetName and in this method add my code.

So what is the difference? When is the point when it’s not good to put some code to getter / setter and when to create own method that is used to change my property and other parts of my class?

Answer 1

Here is a good set of guidelines for when to use properties vs methods from Bill Wagner (fixed link)

• Use a Property when all these are true:
  The getters should be simple and thus unlikely to throw exceptions. Note that this implies no network (or database) access. Either might fail, and therefore would throw an exception.
• They should not have dependencies on each other. Note that this would include setting one property and having it affect another. (For example, setting the FirstName property would affect a read-only FullName property that composed the first name + last name properties implies such a dependency )
• They should be settable in any order
• The getter does not have an observable side effect Note this guideline doesn’t preclude some forms of lazy evaluation in a property.
• The method must always return immediately. (Note that this precludes a property that makes a database access call, web service call, or other similar operation).
• Use a method if the member returns an array.
• Repeated calls to the getter (without intervening code) should return the same value.

• Repeated calls to the setter (with the same value) should yield no difference from a single call.

• The get should not return a reference to internal data structures (See item 23). A method could return a deep copy, and could avoid this issue.