var propertyType = propertyInfo.PropertyType;

if (propertyType.IsGenericType &&

        propertyType.GetGenericTypeDefinition() == typeof(Nullable<>))

    {

      propertyType = propertyType.GetGenericArguments()[0];

    }

model.ModelProperties.Add(new KeyValuePair<Type, string>

                        (propertyType.Name,propertyInfo.Name));