As in the case of Ice objects, a Dynamic Ice application may represent user exceptions in a native format that is not directly compatible with the Ice API. If the application needs to raise such a user exception to the Ice run time, the exception must be wrapped in a subclass of Ice.UserException. The Dynamic Ice API provides a class to simplify this process:

{zcode:cs}
namespace Ice
{
    public abstract class UserExceptionWriter : UserException
    {
        public UserExceptionWriter(Communicator communicator);

        public abstract void write(OutputStream os);
        public abstract bool usesClasses();

        // ...
    }
}
{zcode}

A subclass of UserExceptionWriter is responsible for supplying a communicator to the constructor, and for implementing the following methods:

• void write(OutputStream os)
  This method is invoked when the Ice run time is ready to marshal the exception. The subclass must marshal the exception using the encoding rules for exceptions.

• bool usesClasses()
  Return true if the exception, or any base exception, contains a data member that is an object by value.

See Also

• Intercepting Object Insertion and Extraction in C-Sharp
• Data Encoding for Exceptions