Question

I read some article regarding expando object here but I want to achieve different thing.
I want to add property object with dynamic property at runtime, put value on it and then retrieve later:

    private static readonly ConditionalWeakTable<object, ExpandoObject> props = new ConditionalWeakTable<object, ExpandoObject>();
    public static void AddDataExtension(this object key, dynamic value)
    {
        props.Add(key, value);
    }

    public static dynamic GetDataExtension(this object key)
    {
        ExpandoObject ex = null;
        return props.TryGetValue(key, out ex);
    }  

Usage:

'Insert data at runtime'
instance.AddDataExtension("Hello", "hi");

'Get the data at runtime'
instance.GetDataExtension("Hello")  

But I receive this error:

The best overloaded method match for 'System.Runtime.CompilerServices.ConditionalWeakTable<object,System.Dynamic.ExpandoObject>.Add(object, System.Dynamic.ExpandoObject)' has some invalid arguments  

I think I misused this property, is this possible to achieve? if yes, how? Please help.

Edit

here is the complete class:

public static class instance
{
    private static readonly ConditionalWeakTable<object, ExpandoObject> props = new ConditionalWeakTable<object, ExpandoObject>();
        public static void AddDataExtension(this object key, dynamic value)
        {
            props.Add(key, value);
        }

        public static dynamic GetDataExtension(this object key)
        {
            ExpandoObject ex = null;
            return props.TryGetValue(key, out ex);
        } 
}  

What I want to achieve is this:
I will have random varialbes, for example, “photo_01, photo_12, photo_15, name_01, name_02, age_01, age_02“
If possible I want to use the method in this way:

id = <fetch from dbase>
instance.AddDataExtension("photo_" + id, byte[]);  

And then retrieve the value:

instance.GetDataExtension("photo_" + id)  

Answer 1

It is not possible because ExpandoObject is sealed.