// CORBA IDL

module demo
{
   module grid 
   { 
      exception MyException
      {
         string why;
      };
   };
};

e.g.
MyException
MyExceptionHelper

// C# 

[Serializable]
public sealed class MyException : Org.Omg.CORBA.UserException
{
   /**
   * Exception member why
   */
   public string why;

   /**
   * Default constructor
   */
   public MyException() : base(MyExceptionHelper.Id())
   {
   }

   /**
   * Constructor with fields initialization
   * @param why why exception member
   */
   public MyException(string why) : base(MyExceptionHelper.Id())
   {
      this.why = why;
   }

   /**
   * Full constructor with fields initialization
   * @param why why exception member
   */
   public MyException(string orb_reason, string why)
      : base (MyExceptionHelper.Id() +" " +  orb_reason)
   {
      this.why = why;
   }

}

public class MyExceptionHelper
{
   ///
   /// Insert MyException into an any
   /// @param a an any
   /// @param t MyException value
   ///
   public static void Insert(Org.Omg.CORBA.Any a, demo.grid.MyServerPackage.MyException t )
   {
      a.Type(Type());
      Write(a.Create_Output_Stream(),t);
   }

   ///
   /// Extract MyException from an any
   /// @param a an any
   ///  @return the extracted MyException value
   ///
   public static demo.grid.MyServerPackage.MyException Extract(Org.Omg.CORBA.Any a)
   {
      if (!a.Type().Equal(Type()))
         throw new Org.Omg.CORBA.MARSHAL();
      return Read(a.Create_Input_Stream());
   }

   ///
   /// Internal TypeCode value
   ///
   private static Org.Omg.CORBA.TypeCode _tc = null;
   private static bool _working = false;

   ///
   /// Return the MyException TypeCode
   /// @return a TypeCode
   ///
   public static Org.Omg.CORBA.TypeCode Type()
   {
      if (_tc == null)
      {
         lock (typeof(Org.Omg.CORBA.TypeCode))
         {
            if (_tc != null)
               return _tc;
            if (_working)
               return Org.Omg.CORBA.ORB.Init().Create_Recursive_TC(Id());
            _working = true;
            Org.Omg.CORBA.ORB orb = Org.Omg.CORBA.ORB.Init();
            Org.Omg.CORBA.StructMember[] _members = new Org.Omg.CORBA.StructMember[1];

            _members[0] = new Org.Omg.CORBA.StructMember();
            _members[0].name = "why";
            _members[0].type = orb.Get_Primitive_TC(Org.Omg.CORBA.TCKind.tk_string);
            _tc = orb.Create_Exception_TC(Id(),"MyException",_members);
            _working = false;
         }
      }
      return _tc;
   }

   ///
   /// Return the MyException IDL ID
   /// @return an ID
   ///
   public static string Id()
   {
      return _id;
   }

   private static string _id = "IDL:demo/grid/MyServer/MyException:1.0";

   ///
   /// Read MyException from a marshalled stream
   /// @param istream the input stream
   /// @return the readed MyException value
   ///
   public static demo.grid.MyServerPackage.MyException Read(
                        Org.Omg.CORBA.Portable.InputStream istream)
   {
      demo.grid.MyServerPackage.MyException new_one = 
                           new demo.grid.MyServerPackage.MyException();

      if (!istream.Read_String().Equals(Id()))
         throw new Org.Omg.CORBA.MARSHAL();
      new_one.why = istream.Read_String();

      return new_one;
   }

   ///
   /// Write MyException into a marshalled stream
   /// @param ostream the output stream
   /// @param value MyException value
   ///
   public static void Write(Org.Omg.CORBA.Portable.OutputStream ostream, 
                            demo.grid.MyServerPackage.MyException value)
   {
      ostream.Write_String(Id());
      ostream.Write_String(value.why);
   }
}