I have a large class with complex properties. I’d like to introduce a default implementation, allow the user to override part of the default implementation and also make sure the user calls a sync method so that the object is always at a consistent state.

public class Complex {     public int Id { get; set; }     public CustomComplex1 Custom1 { get; set; }     public CustomComplex2 Custom2 { get; set; }      public Complex()     {         Custom1 = new CustomComplex1() { Name = "Bla", Cost = 55, etc..} // provide default values     }      //this method must always be called!     public void RegisterObject()     {      }      

}

Class could be used like this:

  var a = new Complex(); // all default values set   a.Custom1.Name = "newName"; // I'd like to use the default values, but just change something..   a.RegisterObject(); // problem - client might forget to call this!  

I thought about using the builder pattern, but then I’ll have to provide methods to modify each variation of CustomComplex1 type – too much work & maintenance. From the other hand if I expose Custom1 as a public property it looks like I’m doing the exact opposite of the builder pattern’s intent. So what is a good way to A.allow the user modify any property of my complex object and B.force him to call the RegisterObject on compile time?