C#4 ‘dynamic’ hole

I’m working in a new .Net4 Cloud project to run in Windows Azure. The proof of concept work fine and now I’m working in the real project writing tests and implementing classes.
I need some classes to initialize the Azure storage based on some conventions, in particular during the implementation of my TableStorageInitializer<TTableEntity> and, overall, its test I found a really nice issue with dynamic.
To simplify the situation a little bit have a look to this simplified implementation:

public class TableStorageInitializer<TTableEntity> where TTableEntity : class, new()
{
public void Initialize()
{
InitializeInstance(new TTableEntity());
}

public void InitializeInstance(dynamic entity)
{
entity.PartitionKey = Guid.NewGuid().ToString();
entity.RowKey = Guid.NewGuid().ToString();
}
}

To test it I’m using a private class declared inside the test class:

private class MyClass
{
public string PartitionKey { get; set; }
public string RowKey { get; set; }
public DateTime Timestamp { get; set; }
}

With my very big surprise what happen is shown in this picture:





As you can see dynamic does not work. Even if the debugger can show the right type with its public properties the DLR can’t recognize it.

How solve the situation ? Well… very very easily, old-school Reflection!!!

public void InitializeInstance(object entity)
{
var entityType = entity.GetType();
entityType.GetProperty("PartitionKey").SetValue(entity, Guid.NewGuid().ToString(), null);
entityType.GetProperty("RowKey").SetValue(entity, Guid.NewGuid().ToString(), null);
}

Note: with a public class the dynamic work as expected.