Can I share dlls across AppDomains in my IIS managed web site?

Question

We have a web service written in C# hosted under IIS. We're using AppDomains to separate invocations of a task - each invocation is run in a separate domain. The code does something like the following:

public class Simplified
{
    public void Run()
    {
        AppDomain workDomain = AppDomain.CreateDomain(...);
        var workUnit = (IWorkUnit)workDomain.CreateInstanceAndUnwrap(...);
        workUnit.Execute(...);
        //Done - but keep the workUnit around in case we need it again
    }
}

However, each AppDomain is loading separate copies of our dlls - which accounts for a large chunk of processing time. I understand you can somehow make assemblies load domain neutral so that they are shared across all appdomains. How do I do this for our IIS web service?

Answer 1

Turns out it's as simple as setting

setup.LoaderOptimization = LoaderOptimization.MultiDomain;

on the AppDomainSetup object used to create the domain. This works fine under IIS