How to find all the classes which implement a given interface?

Question

Under a given namespace, I have a set of classes which implement an interface. Let\'s call it ISomething. I have another class (let\'s call it CClass

Answer 1

A working code-sample:

var instances = from t in Assembly.GetExecutingAssembly().GetTypes()
                where t.GetInterfaces().Contains(typeof(ISomething))
                         && t.GetConstructor(Type.EmptyTypes) != null
                select Activator.CreateInstance(t) as ISomething;

foreach (var instance in instances)
{
    instance.Foo(); // where Foo is a method of ISomething
}

Edit Added a check for a parameterless constructor so that the call to CreateInstance will succeed.