Json and Circular Reference Exception

Question

I have an object which has a circular reference to another object. Given the relationship between these objects this is the right design.

To Illustrate

Answer 1

I'm answering this despite its age because it is the 3rd result (currently) from Google for "json.encode circular reference" and although I don't agree with the answers (completely) above, in that using the ScriptIgnoreAttribute assumes that you won't anywhere in your code want to traverse the relationship in the other direction for some JSON. I don't believe in locking down your model because of one use case.

It did inspire me to use this simple solution.

Since you're working in a View in MVC, you have the Model and you want to simply assign the Model to the ViewData.Model within your controller, go ahead and use a LINQ query within your View to flatten the data nicely removing the offending circular reference for the particular JSON you want like this:

var jsonMachines = from m in machineForm
                   select new { m.X, m.Y, // other Machine properties you desire
                                Customer = new { m.Customer.Id, m.Customer.Name, // other Customer properties you desire
                              }};
return Json(jsonMachines);

Or if the Machine -> Customer relationship is 1..* -> * then try:

var jsonMachines = from m in machineForm
                   select new { m.X, m.Y, // other machine properties you desire
                                Customers = new List(
                                               (from c in m.Customers
                                                select new Customer()
                                                {
                                                   Id = c.Id,
                                                   Name = c.Name,
                                                   // Other Customer properties you desire
                                                }).Cast())
                               };
return Json(jsonMachines);