Static Fields in AppDomain

It looks like you are loading a type from another appDomain into the current appDomain. Thus the code that calls the static methods are calling from the current appDomain.

I’m unaware of any other way to call a static method in another domain without creating an instance of an object in another domain, and having that object call the static method.

Example: Solution contains 2 Projects (ClassLibrary and a Winforms/Console app)

[ClassLibrary]

using System;

namespace MyLibrary
{
    public class DomainObject : MarshalByRefObject
    {
        private static int _Value;

        private static void IncrementValue()
        {
            DomainObject._Value++;
        }

        public static int Value
        {
            get
            {
                return DomainObject._Value;
            }
        }

        public int GetIncrementedValue()
        {
            DomainObject.IncrementValue();
            return DomainObject.Value;
        }
    }
}

[Application]

private void button1_Click(object sender, EventArgs e)
{
    AppDomain domain1 = AppDomain.CreateDomain("domain1");
    AppDomain domain2 = AppDomain.CreateDomain("domain2");

    DomainObject object1 = 
        domain1.CreateInstanceAndUnwrap("MyLibrary", "MyLibrary.DomainObject") 
        as DomainObject;

    DomainObject object2 = 
        domain2.CreateInstanceAndUnwrap("MyLibrary", "MyLibrary.DomainObject") 
        as DomainObject;

    if (object1 != null)
    {
        Console.WriteLine("object 1 Value = " 
                          + object1.GetIncrementedValue().ToString());
        Console.WriteLine("object 1 Value = " 
                          + object1.GetIncrementedValue().ToString());
        Console.WriteLine("object 1 Value = " 
                          + object1.GetIncrementedValue().ToString());
    }
    if (object2 != null)
    {
        Console.WriteLine("object 2 Value = "
                          + object2.GetIncrementedValue().ToString());
        Console.WriteLine("object 2 Value = "
                          + object2.GetIncrementedValue().ToString());
        Console.WriteLine("object 2 Value = "
                          + object2.GetIncrementedValue().ToString());
    }

    /* Unload the Domain and re-create
     * This should reset the Static Value in the AppDomain
     */
    AppDomain.Unload(domain1);
    domain1 = AppDomain.CreateDomain("domain1");
    object1 = domain1.CreateInstanceAndUnwrap("MyLibrary", 
                                              "MyLibrary.DomainObject") 
                                              as DomainObject;

    if (object1 != null)
    {
        Console.WriteLine("object 1 Value = "
                          + object1.GetIncrementedValue().ToString());
        Console.WriteLine("object 1 Value = "
                          + object1.GetIncrementedValue().ToString());
        Console.WriteLine("object 1 Value = "
                          + object1.GetIncrementedValue().ToString());
    }
    if (object2 != null)
    {
        Console.WriteLine("object 2 Value = "
                          + object2.GetIncrementedValue().ToString());
        Console.WriteLine("object 2 Value = "
                          + object2.GetIncrementedValue().ToString());
        Console.WriteLine("object 2 Value = "
                          + object2.GetIncrementedValue().ToString());
    }
}

Generated Results:

object 1 Value = 1
object 1 Value = 2
object 1 Value = 3
object 2 Value = 1
object 2 Value = 2
object 2 Value = 3
object 1 Value = 1
object 1 Value = 2
object 1 Value = 3
object 2 Value = 4
object 2 Value = 5
object 2 Value = 6