/// <summary>
/// Selects a node set, using the specified XPath expression.
/// </summary>
/// <param name="navigator">A source XPathNavigator.</param>
/// <param name="expression">An XPath expression.</param>
/// <param name="variables">A set of XPathVariables.</param>
/// <returns>An iterator over the nodes matching the specified expression.</returns>
public static XPathNodeIterator Select(this XPathNavigator navigator, string expression, params XPathVariable[] variables)
{
if (variables == null || variables.Length == 0 || variables[0] == null)
{
return(navigator.Select(expression));
}
// Reflector shows that the standard XPathNavigator.Compile method just does
// return XPathExpression.Compile(xpath);
// only difference is, XPathNavigator.Compile is virtual so it could be overridden
// by a class inheriting from XPathNavigator... there does not seem to be any
// doing it in the Framework, though... so we'll assume it's much cleaner to use
// the static compile:
var compiled = XPathExpression.Compile(expression);
var context = new DynamicContext();
foreach (XPathVariable variable in variables)
{
context.AddVariable(variable.Name, variable.Value);
}
compiled.SetContext(context);
return(navigator.Select(compiled));
}
/// <summary>
/// Selects a node set, using the specified XPath expression.
/// </summary>
/// <param name="navigator">A source XPathNavigator.</param>
/// <param name="expression">An XPath expression.</param>
/// <param name="variables">A set of XPathVariables.</param>
/// <returns>An iterator over the nodes matching the specified expression.</returns>
public static XPathNodeIterator Select(this XPathNavigator navigator, XPathExpression expression, params XPathVariable[] variables)
{
if (variables == null || variables.Length == 0 || variables[0] == null)
{
return(navigator.Select(expression));
}
var compiled = expression.Clone(); // clone for thread-safety
var context = new DynamicContext();
foreach (var variable in variables)
{
context.AddVariable(variable.Name, variable.Value);
}
compiled.SetContext(context);
return(navigator.Select(compiled));
}
