This exception indicates a problem with an XPathExpression , such as an invalid prefix. public class XPathException : SystemException { // Public Constructors public XPathException (string message , Exception innerException ); // Protected Constructors protected XPathException (System.Runtime.Serialization.SerializationInfo info , System.Runtime.Serialization.StreamingContext context ); // Public Instance Properties public override string Message {get; } // overrides Exception // Public Instance Methods public override void GetObjectData (System.Runtime.Serialization.SerializationInfo info , System.Runtime.Serialization.StreamingContext context ) // overrides Exception } HierarchySystem.Object System.Exception(System.Runtime.Serialization.ISerializable) System.SystemException XPathException |