Exemple #1
0
        /// <summary>
        /// Creates new instance of the map entry defined by this node.
        /// </summary>
        /// <param name="context">Context to evaluate expressions against.</param>
        /// <param name="evalContext">Current expression evaluation context.</param>
        /// <returns>Node's value.</returns>
        protected override object Get(object context, EvaluationContext evalContext)
        {
            BaseNode firstChild = (BaseNode)this.getFirstChild();
            object   key        = GetValue(firstChild, context, evalContext);
            object   value      = GetValue((BaseNode)firstChild.getNextSibling(), context, evalContext);

            return(new DictionaryEntry(key, value));
        }
        /// <summary>
        /// Returns a <see cref="IList"/> containing results of evaluation
        /// of selection expression against each node in the context.
        /// </summary>
        /// <param name="context">Context to evaluate expressions against.</param>
        /// <param name="evalContext">Current expression evaluation context.</param>
        /// <returns>Node's value.</returns>
        protected override object Get(object context, EvaluationContext evalContext)
        {
            IEnumerable enumerable = context as IEnumerable;

            if (enumerable == null)
            {
                throw new ArgumentException(
                          "Selection can only be used on an instance of the type that implements IEnumerable.");
            }

            BaseNode expression         = (BaseNode)this.getFirstChild();
            BaseNode minIndexExpression = (BaseNode)expression.getNextSibling();
            BaseNode maxIndexExpression = (minIndexExpression == null) ? null : (BaseNode)minIndexExpression.getNextSibling();

            int minIndex = (int)((minIndexExpression == null)
                                      ? Int32.MinValue
                                      : GetValue(minIndexExpression, context, evalContext));
            int maxIndex = (int)((maxIndexExpression == null)
                                      ? Int32.MaxValue
                                      : GetValue(maxIndexExpression, context, evalContext));

            IList selectionList = new ArrayList();

            using (evalContext.SwitchThisContext())
            {
                int found = 0;
                foreach (object o in enumerable)
                {
                    evalContext.ThisContext = o;
                    bool isMatch = (bool)GetValue(expression, o, evalContext);
                    if (isMatch)
                    {
                        if (minIndex <= found && found <= maxIndex)
                        {
                            selectionList.Add(o);
                        }
                        found++;

                        if (found > maxIndex)
                        {
                            break; // don't look any further
                        }
                    }
                }
            }
            return(selectionList);
        }