Use AppDomain to load/unload external assemblies

Question

My scenario is as follows:

• Create new AppDomain
• Load some assemblies into it
• Do some magic with loaded dlls
• Unload AppDomain to rele

Answer 1

Each assembly is loaded into the main domain as well. Since you use Assembly instance, your main domain loads this assembly in order to be able to analyze all the types in it.

If you want to prevent loading assembly in both domains - use AppDomain.CreateInstance method.

Answer 2

Answering my own question - don't know if there's better way to do it on StackOverflow... If there is, I'd be grateful for instructions... Anyway, digging through internet I found another solution, which I hope is better. Code below, if anyone finds any weak points - please respond.

class Program
{
    static void Main(string[] args)
    {
        Console.ReadLine();
        for(int i=0;i<10;i++)
        {
            AppDomain appDomain = AppDomain.CreateDomain("MyTemp");
            appDomain.DoCallBack(loadAssembly);
            appDomain.DomainUnload += appDomain_DomainUnload;

            AppDomain.Unload(appDomain);        
        }

        AppDomain appDomain2 = AppDomain.CreateDomain("MyTemp2");
        appDomain2.DoCallBack(loadAssembly);
        appDomain2.DomainUnload += appDomain_DomainUnload;

        AppDomain.Unload(appDomain2);

        GC.Collect();
        GC.WaitForPendingFinalizers();  
        Console.ReadLine();
    }

    private static void loadAssembly()
    {
        string fullPath = @"E:\tmp\sandbox\AppDomains\AppDomains1\AppDomains1\bin\Debug\BigLib.dll";
        var assembly = Assembly.LoadFrom(fullPath);
        var instance = Activator.CreateInstance(assembly.GetTypes()[0]);
        Console.WriteLine("Creating instance of {0}", instance.GetType());
        Thread.Sleep(2000);
        instance = null;
    }

    private static void appDomain_DomainUnload(object sender, EventArgs e)
    {
        AppDomain ap = sender as AppDomain;
        Console.WriteLine("Unloading {0} AppDomain", ap.FriendlyName);
    }
}