Question

I can’t get dynamic objects to work in types in other assemblies. To replicate this, create a new solution, add a class library, add a console application, add a reference to the class library to the console application, create this class in the class library:

public class DynamicTest
{
    public dynamic People { get; set; }
    public override string ToString()
    {
        var sb = new StringBuilder();

        foreach (var person in People)
        {
            sb.AppendLine(person.Name);
        }

        return sb.ToString();
    }
}

And insert this into the console application’s Program.Main():

var test = new DynamicTest
{
    People = new[] { 
        new { Name = "John" },
        new { Name = "Jane" }
    }
};

Console.WriteLine(test.ToString());
Console.ReadLine();

Run the console application. On the sb.AppendLine line in the DynamicTest class, a RuntimeBinderException is thrown with the message 'object' does not contain a definition for 'Name'.

If I move the DynamicTest class into the console application assembly it works as expected. Is there a limitation with using dynamic across assemblies? This seems to be a pretty reasonable use case for dynamic.

Answer 1

The general consensus for this is to use an ExpandoObject – which is the equivalent that can cross app boundaries.

EDIT: Man, I forgot how the compiler treated dynamic until now.. it’s fascinating.