Casting anonymous type to dynamic

gdoron is supporting Monica picture gdoron is supporting Monica · Dec 11, 2011 · Viewed 17.1k times · Source

I have a function that returns an anonymous type which I want to test in my MVC controller.

public JsonResult Foo()
{
    var data = new
                  {
                      details = "something",
                      more = "More"
                  };
    return Json(data);
}

I want to verify the data I get from the Foo function, What I'm doing now is getting the data type and get it's properties values with reflection.

[Test]
public void TestOne()
{
    var data = _controller.Foo().Data;
    var details = data.GetType().GetProperty("details").GetValue(data, null);
    var more = data.GetType().GetProperty("more").GetValue(data, null);

    Assert.AreEquals("something", details);
    Assert.AreEquals("More", more);
}

Is there a simple way similar to this to check the anonymous properties?

[Test]
public void TestTwo()
{
    var data = (dynamic) _controller.Foo().Data;
    var details = data.details; // RunTimeBinderException object does not contain definition for details
    var more = data.more;

    Assert.AreEquals("something", details);
    Assert.AreEquals("More", more);
}

Answer

Marc Gravell picture Marc Gravell · Dec 11, 2011

Anonymous objects are internal, which means their members are very restricted outside of the assembly that declares them. dynamic respects accessibility, so pretends not to be able to see those members. If the call-site was in the same assembly, I expect it would work.

Your reflection code respects the member accessibility, but bypasses the type's accessibility - hence it works.

In short: no.