title: Postsharp Newbie - Why is args.Instance null?
body: <p>New to PostSharp --- I'm trying out the NuGet version now and I'm trying to understand wny in the AuthoriseAttribute OnEntry method that the agrs.Instance value is null. I'm trying to implement authorsation that depends on the values of the object e.g. A customer who's been archived can't have a credit limit raised. I'm implementing the rules within other classes specific to the rules. </p>
  
  <pre><code>public class Program
  {
      static void Main(string[] args)
      {
          var c = new Customer();
          c.RaiseCreditLimit(100000);
          c.Error(00); 
      }
  }
  
  public class Customer
  {
      [AuthorizeActivity]
      public void RaiseCreditLimit(int newValue)
      {
      }
  
      [AuthorizeActivity]
      public void Error(int newValue)
      {
  
      }
  }
  
  [Serializable]
  public class AuthorizeActivityAttribute : OnMethodBoundaryAspect
  {
      public override void OnEntry(MethodExecutionArgs args)
      {
          //
          //Why is args.Instance null???????????
          //
          if (args.Method.Name == "RaiseCreditLimit")
          {
              Debug.WriteLine(args.Method.Name + " started");
          }
          else
          {
              throw new Exception("Crap");
          }
      }
  
      public override void OnExit(MethodExecutionArgs args)
      {
          Debug.WriteLine(args.Method.Name + " finished");
      }
  }
  </code></pre>