c# - Add property to anonymous type after creation

Question

I use an anonymous object to pass my Html Attributes to some helper methods. If the consumer didn't add an ID attribute, I want to add it in my helper method.

How can I add an attribute to this anonymous object?

Answer 1

The following extension class would get you what you need.

public static class ObjectExtensions
{
    public static IDictionary<string, object> AddProperty(this object obj, string name, object value)
    {
        var dictionary = obj.ToDictionary();
        dictionary.Add(name, value);
        return dictionary;
    }

    // helper
    public static IDictionary<string, object> ToDictionary(this object obj)
    {
        IDictionary<string, object> result = new Dictionary<string, object>();
        PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(obj);
        foreach (PropertyDescriptor property in properties){
            result.Add(property.Name, property.GetValue(obj));
        }
        return result;
    }
}