Question

I have a big dictionary of (string, object). The values in the dictionary are of different types. Only at run time I can find the exact type of the values in the dictionary of (string, int) or (string, string). At run time I have to assign the values in the dictionary to their corresponding strongly typed objects. This is the simplified problem.
I’m trying to use a typed class that does the cast.
I have this code that does not work:

static void Main(string[] args)
{
    var values = new Dictionary<string, object> 
    { 
        { "123", "test"},
        {"12", 123}
    };
    var result = new Dictionary<string, object> ();

    Type dict = values.GetType();
    Type typedCast = typeof(TypedClass<>).MakeGenericType(new [] { dict });
    MethodInfo method = typedCast.GetMethod("GetTypedValue", 
        BindingFlags.Static | BindingFlags.Public, 
        null, 
        new[]
            {
                  typeof(object), 
                  typeof(object).MakeByRefType()
            },
        null);

    method.Invoke(null, new[]{values, result});
}

public class TypedClass<T>
{
    public static void GetTypedValue(object value, out object obj)
    {
        obj = (T)Convert.ChangeType(value, typeof(T));
    }
}

Inside the GetTypedValue method I see the obj value with the correct type, but outside this method the out variable has no values. Please let me know what am I doing wrong.

Answer 1

Try replacing:

method.Invoke(null, new[]{values, result});

with

var invokeArgs = new[]{values, result};
method.Invoke(null, invokeArgs);
//here you can check the invokeArgs[1] for the actual result of the conversion

In any case, I’m not sure why you would want to convert the type of a Dictionary to another Dictionary, because that’s what your code seems to do…