Under what conditions will `RealProxy.GetTransparentProxy()` return `null`?

The documentation at http://msdn.microsoft.com/en-us/library/system.runtime.remoting.proxies.realproxy.gettransparentproxy%28v=VS.100%29.aspx doesn't indicate a scenari开发者_如何学Goo where GetTransparentProxy will return null, but I'm getting a null back when I call it.

What circumstances will cause this behavior?

Nevermind, solved it. Its critical to have your RealProxy derived class call the base constructor with the type to be proxied. In my case:

public class MyProxy<T> : RealProxy
{
    public MyProxy()
        : base(typeof(T))    // this was missing
    {
        ...
    }

    ...
}