Check if XML Element exists

How can someone validate that a specific element exists in an XML file? Say I have an ever changing XML file and I need to verify every element exists before reading/parsing it.

if(doc.SelectSingleNode("//mynode")==null)....

Should do it (where doc is your XmlDocument object, obviously)

Alternatively you could use an XSD and validate against that

You can iterate through each and every node and see if a node exists.

doc.Load(xmlPath);
        XmlNodeList node = doc.SelectNodes("//Nodes/Node");
        foreach (XmlNode chNode in node)
        {
            try{
            if (chNode["innerNode"]==null)
                return true; //node exists
            //if ... check for any other nodes you need to
            }catch(Exception e){return false; //some node doesn't exists.}
        }

You iterate through every Node elements under Nodes (say this is root) and check to see if node named 'innerNode' (add others if you need) exists. try..catch is because I suspect this will throw popular 'object reference not set' error if the node does not exist.