C# ‘dynamic’ cannot access properties from anonymous types declared in another assembly

Question

Code below is working well as long as I have class ClassSameAssembly in same assembly as class Program. But when I move class ClassSameAssemb

Answer 1

I ran into a similair problem and would like to add to Jon Skeets answer that there is another option. The reason I found out was that I realized that many extension methods in Asp MVC3 uses anonymous classes as input to provide html attributes (new {alt="Image alt", style="padding-top: 5px"} =>

Anyway - those functions use the constructor of the RouteValueDictionary class. I tried that myself, and sure enough it works - though only the first level (I used a multi-level structure). SO - in code this would be:

object o = new {
    name = "theName",
    props = new {
        p1 = "prop1",
        p2 = "prop2"
    }
}
SeparateAssembly.TextFunc(o)

//In SeparateAssembly:
public void TextFunc(Object o) {
  var rvd = new RouteValueDictionary(o);

//Does not work:
Console.WriteLine(o.name);
Console.WriteLine(o.props.p1);

//DOES work!
Console.WriteLine(rvd["name"]);

//Does not work
Console.WriteLine(rvd["props"].p1);
Console.WriteLine(rvd["props"]["p1"]);

SO... What is really going on here? A peek inside the RouteValueDictionary reveals this code (values ~= o above):

foreach (PropertyDescriptor descriptor in TypeDescriptor.GetProperties(values))
    object obj2 = descriptor.GetValue(values);
    //"this.Add" would of course need to be adapted
    this.Add(descriptor.Name, obj2);
}

SO - using TypeDescriptor.GetProperties(o) we would be able to get the properties and values despite the anonymous type being constructed as internal in a separate assembly! And of course this would be quite easy to extend to make it recursive. And to make an extension method if you wanted.

Hope this helps!

/Victor