Get interface properties of object through property declaration

I want to get the interface properties if they exist from the container object of the property. I can get the container class, I think, but the interface of doing "as ISportParameters" returns null, but the interface is certainly on the object.

public class CustomModelMetadataProvider : DataAnnotationsModelMetadataProvider
    {
        protected override ModelMetadata CreateMetadata(IEnumerable<Attribute> attributes, Type containerType, Func<object> modelAccessor, Type modelType, string propertyName)
        {
            var modelMetadata = base.CreateMetadata(attributes, containerType, modelAccessor, modelType, propertyName);

            if (attributes.OfType<DisplayAttribute>().ToList().Count > 0)
            {
                 // Want ISportParameters properties
                var model = modelAccessor.Target.GetType().GetField("container").GetValue(modelAccessor.Target);

            }

            return modelMetadata;
        }

}