Question

I have code to implement GoF’s proxy pattern in C#. The code has MathProxy for calculating arithmetic functions.

The left side example is one implementation, and the right side is the better one for C# (.NET) with AppDomain.

What benefits can I expect using AppDomain especially with Proxy Pattern?

public MathProxy()
{
    // Create Math instance in a different AppDomain
    var ad =  AppDomain.CreateDomain("MathDomain", null, null);

    var o = ad.CreateInstance(
        "DoFactory.GangOfFour.Proxy.NETOptimized",
        "DoFactory.GangOfFour.Proxy.NETOptimized.Math");
    _math = (Math)o.Unwrap();
}

Answer 1

Any given Windows process that hosts the CLR can have one or more application domains defined that contain the executable code, data, metadata structures, and
resources. In addition to the protection guarantees built in by the process, an application domain further introduces the following guarantees:

• Faulty code within an application domain cannot adversely affect code running in a different application domain within the same process.
• Code running within an application domain cannot directly access resources in a different application domain.
• Code-specific configurations can be configured on a per application domain basis. For example, you can configure security-specific settings on a per application
  domain basis.