Question

Basically I have a list of objects where each object might implement a different set of interfaces:

List<BaseObject> objects;

class BaseObject
{
  public void DoStuff();
}

interface IX
{
  void DoX();
}

interface IY
{
  void DoY();
}

interface IZ
{
  void DoZ();
}

And i would like to write something like this:

foreach(var obj in objects.OfType<BaseObject and IX>)
{
  obj.DoStuff();
  obj.DoX();
}

(E.g. i perform a specific algorithm for objects of type BaseObject and IX without having to do typecasts there)

Is it possible to do in C#?
What’s the most elegant solution?

I can do this:

foreach(var obj in objects.OfType<IX>)
{
  var baseobj = (BaseObject)obj.DoStuff();
  obj.DoX();
}

But i find it ugly.

And I might need to apply specific operations to types that implement say interface IX and interface IZ.

foreach(var obj in objects.OfType<BaseType and IX and IZ>)
{
  obj.DoStuff();
  obj.DoX();
  obj.DoZ();
}

Answer 1

One possible way is to use dynamic:

foreach(var xz in objects.Where(o => o is IX && o is IZ).Select(o => (dynamic)o))
{
    xz.DoStuff();
    xz.DoX();
    xz.DoZ();   
}

Of course, you can still cast if you don’t want to use dynamic:

foreach(var xz in objects.Where(o => o is IX && o is IZ))
{
    xz.DoStuff();
    ((IX)xz).DoX();
    ((IZ)xz).DoZ(); 
}