c# - Adding unknown (at design time) properties to an ExpandoObject

Question

just exploring c# 4. Trying to get my head around all this dynamic stuff. Sorry if this question is silly, no experience in this domain.

If I have an ExpandoObject and want to add public properties (with get and set) to it at runtime, how would I go about doing it?

For example, I have a documentTemplate and a document, which has a property pointing towards the documentTemplate. This documentTemplate has got some tag Titles (eg. Capabilities developed among students), which should be addressed while making the document (eg. Concentration, memory etc.). So as soon as the template is set in the document, I want to create a class, which has properties with same names as the tag titles in the Template, and then using some UI element, such as the PropertyGrid, I can have the user fill in tag values against the tag Titles.

Thanks for reading!

Answer 1

I wondered how it might be possible to add members to a class "on the fly" and came up with this sample:

using System;
using System.Collections.Generic;
using System.Dynamic;

class Program
{
    static void Main()
    {
        dynamic expando = new ExpandoObject();
        var p = expando as IDictionary<String, object>;

        p["A"] = "New val 1";
        p["B"] = "New val 2";

        Console.WriteLine(expando.A);
        Console.WriteLine(expando.B);
    }
}

The point of this code snippet is that the members A and B are defined as string literals (hard coded/stringified) in and added via ExpandoObject's IDictionary interface. We test for the keys' existence and values (and prove the concept) by accessing them directly and outputting to console.