protected ITargetObject GetStaticField(ITargetStructType stype, StackFrame frame, ITargetFieldInfo field)
 {
     try {
         return stype.GetStaticField (frame, field.Index);
     } catch (Mono.Debugger.TargetInvocationException ex) {
         throw new EvaluationException ("Can't get field {0}: {1}", Name, ex.Message);
     }
 }
 protected ITargetObject GetField(ITargetStructObject sobj, ITargetFieldInfo field)
 {
     try {
         return sobj.GetField (field.Index);
     } catch (Mono.Debugger.TargetInvocationException ex) {
         throw new EvaluationException ("Can't get field {0}: {1}", Name, ex.Message);
     }
 }