How is memory allocated when passing inherited class as param to a method using this keyword?

I am a junior developer and I am not sure if the sample code below is a good practice. I would like to know if there is a performance impact by passing current class instan开发者_运维百科ce as a parameter of a method. Also what could be the performance impact by passing it to several methods? Please advise on the code below.

Class X: Y
{

  Z myObject = new Z();
   myObject.MethodA( (Y)this);
}


Class Z
{

   MethodA(Y y)
  {
     y.Mystream = Write Element
     MethodB(ref y)
     MethodC(ref y)

   }
   MethodB(ref Y y)
  {
     y.Mystream = Write Element

   }
 }


Class Y
{  
    Public XMLTextWriter  Mystream = null;
}

In the first case (MethodA(this)), a copy of the reference is passed by value to the method. This is blazingly fast. I guarantee it's not a bottleneck in your application.

In the second case (MethodB(ref y)), the storage location of the reference is passed to the method. This is blazingly fast. I guarantee it's not a bottleneck in your application.