This is an offshoot question that's related to another I asked here. I'm splitting it off because it's really a sub-question:

I'm having difficulties casting an object of type dynamic to another (known) static type.

I have an ironPython script that is doing this:

import clr
clr.AddReference("System")
from System import *

def GetBclUri():
    return Uri("http://google.com")

note that it's simply newing up a BCL System.Uri type and returning it. So I know the static type of the returned object.

now over in C# land, I'm newing up the script hosting stuff and calling this getter to return the Uri object:

dynamic uri = scriptEngine.GetBclUri();
System.Uri u = uri as System.Uri; // casts the dynamic to static fine

Works no problem. I now can use the strongly typed Uri object as if it was originally instantiated statically.

however....

Now I want to define my own C# class that will be newed up in dynamic-land just like I did with the Uri. My simple C# class:

namespace Entity
{
    public class TestPy // stupid simple test class of my own
    {
        public string DoSomething(string something)
        {
            return something;
        }
    }
}

Now in Python, new up an object of this type and return it:

sys.path.append(r'C:..path here...')
clr.AddReferenceToFile("entity.dll")
import Entity.TestPy

def GetTest():
    return Entity.TestPy(); // the C# class

then in C# call the getter:

dynamic test = scriptEngine.GetTest();
Entity.TestPy t = test  as Entity.TestPy; // t==null!!!

here, the cast does not work. Note that the 'test' object (dynamic) is valid--I can call the DoSomething()--it just won't cast to the known static type

string s = test.DoSomething("asdf"); // dynamic object works fine

so I'm perplexed. the BCL type System.Uri will cast from a dynamic type to the correct static one, but my own type won't. There's obviously something I'm not getting about this...