Interceptor

If you require extracting positional strings and converting the values into their final forms, such as obtaining a string representing a datetime or decimal currency format, you can create an interceptor reader by implementing the IInterceptor interface. This allows you to perform custom actions before the value is set to the final property.

here and example of intercept the property read.

    public class WebSiteInterceptor : IInterceptor
    {
        public object Parse(object propertyValue)
        {
            return $"WebSite: {propertyValue.ToString()}";
        }
    }
        
    [ReadProperty(start: 9, length: 20, type: typeof(WebSiteInterceptor))]