IXPathEvaluator.Evaluate

IXPathEvaluator.Evaluate method

Evaluates an XPath expression string and returns a result of the specified type if possible.

public IXPathResult Evaluate(string expression, Node contextNode, IXPathNSResolver resolver, 
    XPathResultType type, object result)

Parameter	Type	Description
expression	String	The XPath expression string to be parsed and evaluated.
contextNode	Node	The `context` is context node for the evaluation of this XPath expression. If the `IXPathEvaluator` was obtained by casting the `Document` then this must be owned by the same document and must be a `Document`, `Element`, `Attr`, `Text`, `CDATASection`, `Comment`, `ProcessingInstruction`, or XPathNamespace node. If the context node is a `Text` or a `CDATASection`, then the context is interpreted as the whole logical text node as seen by XPath, unless the node is empty in which case it may not serve as the XPath context.
resolver	IXPathNSResolver	The `resolver` permits translation of all prefixes, including the `xml` namespace prefix, within the XPath expression into appropriate namespace URIs. If this is specified as `null`, any namespace prefix within the expression will result in `DOMException` being thrown with the code `NAMESPACE_ERR`.
type	XPathResultType	If a specific `type` is specified, then the result will be returned as the corresponding type. For XPath 1.0 results, this must be one of the values of the `XPathResultType` enum.
result	Object	The `result` specifies a specific result object which may be reused and returned by this method. If this is specified as `null` or the implementation does not reuse the specified result, a new result object will be constructed and returned. For XPath 1.0 results, this object will be of type `IXPathResult`.

The result of the evaluation of the XPath expression. For XPath 1.0 results, this object will be of type IXPathResult.

exception	condition
DOMException	INVALID_EXPRESSION_ERR: Raised if the expression is not legal according to the rules of the `IXPathEvaluator`.
DOMException	TYPE_ERR: Raised if the result cannot be converted to return the specified type.
DOMException	NAMESPACE_ERR: Raised if the expression contains namespace prefixes which cannot be resolved by the specified `IXPathNSResolver`.
DOMException	WRONG_DOCUMENT_ERR: The Node is from a document that is not supported by this `IXPathEvaluator`.
DOMException	NOT_SUPPORTED_ERR: The Node is not a type permitted as an XPath context node or the request type is not permitted by this `IXPathEvaluator`.