public void Foo(object o)
{
if (o == null)
{
throw new NullRefferenceException("Null reference", "o");
}
IFooable f = o as IFooable;
if (f != null)
{
f.Foo();
}
else
{
throw new ArgumentException("Unexpected type: " + o.GetType());
}
}
public void ProcessFooBars(IList <IFooBar> foobars)
{
foreach (var foobar in foobars)
{
// feature detection to see which interfaces the instance implements
IBarrable bar = foobar as IBarrable;
if (bar != null)
{
bar.Bar();
}
IFooable foo = foobar as IFooable;
if (foo != null)
{
foo.Foo();
}
}
}