Question

Sometimes data is deleted from a database by a user which has been referred to. A try catch in razor will handle this just fine, but is there another way?

Current Situation: The model holds a list of Boxes. Each Box has a Container. Safeguarding against Container deletion to avoid errors means using try catch.

No error handling,

<td>@m.Container.Name</td>

Error handling,

<td>@try{@m.Container.Name}catch { Deleted }</td>

Many lists have similar situations, where it is possible that relational data may be removed. Is there a better way to accomplish this aside from this try catch approach?

Some extra code to help with the example:

View Model:

public class BoxVM
{
 List<Box> Boxes { get; set; }
}

Models:

public class Box
{
 public int BoxId { get; set; }
 public Material Material { get; set; }
 public Container Container { get; set; }
}

public class Material
{
 //fk
 public int BoxId { get; set; }
 public string Description { get; set; }
}

public class Container
{
 //fk
 public int BoxId { get; set; }
 public string Name { get; set; }
}

Controller:

public ActionResult showBoxList()
{
 var vm = new BoxVM();
 vm.boxes = _boxRepo.Get().ToList();
 var materials = _materialRepo.Get().ToList();
 var containers = _containerRepo.Get().ToList();
 foreach(var box in vm.boxes)
 {
  box.Material = materials.Where(m => m.BoxId == box.BoxId).Single();
  box.Container = containers.Where(c => c.BoxId == box.BoxId).Single();
 }
 return View(vm);
}

View:

@model BoxVM

foreach(var m in Model.boxes)
{
 <p>@m.Container.Name</p> @*// Breaks if specific container was deleted *@
 <p>@try{@m.Container.Name}catch{<text>Deleted</text>}</p> @*// Doesn't break, but is there a better way? *@
}

Answer 1

Is there a better way to accomplish this aside from this try catch approach?

Yes. Use an approach which supports a verbose referential integrity policy allowing for the deletion of a single node in an object graph while maintaining the relevance of the object graph.