Declare IDisposable for the class or interface?

Question

Starting from the follwing situation:

public interface ISample
{
}

public class SampleA : ISample
{
   // has some (unmanaged) resources that needs to be di         


        

Answer 1

If you apply the using(){} pattern to all your interfaces it's best to have ISample derive from IDisposable because the rule of thumb when designing interfaces is to favor "ease-of-use" over "ease-of-implementation".