Alex Rivera | Logout

Where should the line between property and method be?

Asked 2010-03-12T22:55:36.533
12

Possible Duplicate:
Properties vs Methods

For many situations it is obvious whether something should be a property or a method however there are items that might be considered ambiguous.

Obvious Properties:

  • "name"
  • "length"

Obvious Methods:

  • "SendMessage"
  • "Print"

Ambiguous:

  • "Valid" / "IsValid" / "Validate"
  • "InBounds" / "IsInBounds" / "CheckBounds"
  • "AverageChildValue" / "CalcAverageChildValue"
  • "ColorSaturation" / "SetColorSaturation"

I suppose I would lean towards methods for the ambiguous, but does anyone know of a rule or convention that helps decide this? E.g. should all properties be O(1)? Should a property not be able to change other data (ColorSaturation might change R,G,B values)? Should it not be a property if there is calculation or aggregation?

Just from an academic perspective, (and not because I think it's a good idea) is there a reason not to go crazy with properties and just make everything that is an interrogation of the class without taking an argument, and everything that can be changed about the class with a single argument and cant fail, a property?

c# properties methods conventions time-complexity
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2 Answers

5

I´ve found some interesting text about this

MSDN | Properties vs Methods

EDIT

It says things like:

Use a property when

  • The member is a logical data member

Use a method when

  • The operation is a conversion, such as Object.ToString.
  • The operation is expensive enough that you want to communicate to the user that they should consider caching the result.
  • Obtaining a property value using the get accessor would have an observable side effect.
  • Calling the member twice in succession produces different results.
  • The order of execution is important. Note that a type's properties should be able to be set and retrieved in any order.
  • The member is static but returns a value that can be changed.
  • The member returns an array. Properties that return arrays can be very misleading.
  • Usually it is necessary to return a copy of the internal array so that the user cannot change internal state. This, coupled with the fact that a user can easily assume it is an indexed property, leads to inefficient code.
answered 2010-03-12T23:02:26.450
0

If you can calculate something from what you already have, use methods, if your value has to be a basis for operating with or calculating something else it should be property.

For example, if you want to check whether certain user input is up to date and you can do it with your unique patented algorithm, use method Validate(). If user just sends you a form submitting nis current address is valid, use property valid. But it is just a common approach that may vary depending on what you actually want.

answered 2010-03-12T23:09:08.827

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