Question

What are the Pro’s Con’s on defining value types as either Methods or Properties on Interfaces

i.e

Are the only issues with threaded apps or are these pretty much interchangable ?

 public interface IFileSearch
    {
        int FilesNum();
        int FilesNum { get; set; }

        bool HasFinsihed { get; set; }

    }

Answer 1

The reason that you wouldn’t want it defined as a method is if the implementor needs the value as a property, for example to send to a web service.

In addition, of course, if the concept you are defining through the interface needs to be both readable and updateable then a property is usually a better solution than two methods (one for setting and one for getting).

If the data is not to be updated, I often vacillate on whether to provide a method or a readonly property, but assuming no additional parameters are required and the concept being exposed is truly a piece of data as opposed to an action, I usually end up on the side of providing a property for databinding, reflection, and serialization purposes.