Code
public   class   User  
{  
   public   int   ID;  
   public   String   Name;  
       
}  
public   class   HelloWorld  
{  
   public   void   Print(ref   User   ui)  
   {  
     Console.WriteLine(ui.Name);//"FileNewExit"  
     ui.Name   =   "Changed";  
   }  
}  
   
class   Ref{  
  static   void   Main(){  
  Type   type   =   typeof(HelloWorld);  
  MethodInfo   mi   =   type.GetMethod("Print");  
  User   user   =   new   User();  
  user.ID   =   1;  
  user.Name   =   "FileNewExit";  
  mi.Invoke(new   HelloWorld(),new   object[]{user});  
  Console.WriteLine(user.Name);//"Changed"  
  }  
}