Getting data back from Child AppDomain

Question

I'm working in a .NET Framework 4.x application.

Say I pass in a object to child AppDomain using SetData(..) method;
- the object is MarshallByRef.
The code running child AppDomain changes the passed in Data. But the value is not getting reflected when the call returns to the parent domain?
Is that by design? Is there a flag/attribute I can set to ensure that data changed is reflected back?

Correction The library was never updated ( to reflect MarhsallByRefObject). The problem fixed itself after using MarshallByRefObject. Performance

What do you mean by "the object is `MarshallByRef`"? (I assume you mean `MarshalByRefObject`), please post your **actual code** where you call `SetData()` and pass values/objects. — Dai, Oct 22 '22 at 00:34
Have you read this? https://stackoverflow.com/questions/1767439/passing-data-across-appdomains-with-marshalbyrefobject — Dai, Oct 22 '22 at 00:35
You do know that AppDomains are gone in .NET Core land, right? Anything you write in .NET 4.x using AppDomains won't survive a port to .NET Core (or 5+). In .NET Framework land, the best way to talk between AppDomains is to use Remoting (also gone in Core-land, I believe). Remoting between two app domains in the same process, using an IPC channel and the Binary Formatter, is _very_ fast. Then again, you'll need to stomache all the caveats about the BinaryFormatter being unsafe — Flydog57, Oct 22 '22 at 03:15
@Flydog57 Yes, I'm aware that AppDomains are gone in .Net Core. Here I'm supporting an older application and want to avoid making revolutionary changes. — Iftikhar Ali, Oct 23 '22 at 21:02
@IftikharAli: yup, just wanted to make sure you knew where you are. I've spent much of my career supporting _old code_ — Flydog57, Oct 23 '22 at 21:09

score 0 · Answer 1 · answered Oct 23 '22 at 21:31

Correction:

The library was never updated ( to reflect MarhsallByRefObject). The problem fixed itself after using MarshallByRefObject.

Here is my sample class

public class MyObject:MarshallByRefObject{
   public string Value = "Test";
   public ChildObject _ChildObj = null;

   public MyObject(){
        _ChildObj = new ChildObject(){ParentRef = this};
       }
}

[Serializable()]
public class ChildObject
{
  public MyObject ParentRef;

}

public class ProcessToRunInChildDomain
{
 
 public ProcessToRunInChildDomain(){
    MyObject obj = (MyObject)AppDomain.CurrentDomain.GetData("obj");
     obj.Value = "Value Set in Child Domain";
}
}

public class Program
{
public static void TestAppDomain(){
   
    var myObj = new MyObject(){ Value = "Value in Parent Domain"};
    var childDomain = CreateADomain_And_LoadProcessToRunInChildDomain();
     childDomain.SetData("obj", myObj);

     //Note: If myObj is not MarshallByRefObject, the changes made
     //in Process will not reflect in Parent Object and below test fails.
       myObj.Value.Should().Be("Value Set in Child Domain");
      
     //Note: The child field type of my MyObject is just Marked 
   //Serializable but parent reference points to the latest values.
       myObj._ChildObj.ParentRef.Value.Should().Be("Value Set in Child Domain");
  }
}

@Dai My issue was that class didn't have MarshallByRefObject inheritance (Compile Issues). Now it is working. See above code sample. — Iftikhar Ali, Oct 23 '22 at 21:33

Getting data back from Child AppDomain

1 Answers1