Check if XML Element exists

Question

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

Answer 1

Not sure what you're wanting to do but using a DTD or schema might be all you need to validate the xml.

Otherwise, if you want to find an element you could use an xpath query to search for a particular element.

Answer 2

How about trying this:

using (XmlTextReader reader = new XmlTextReader(xmlPath))
{
    while (reader.Read())
    {
        if (reader.NodeType == XmlNodeType.Element)
        { 
            //do your code here
        }
    }
}

Answer 3

A little bit late, but if it helps, this works for me...

XmlNodeList NodoEstudios = DocumentoXML.SelectNodes("//ALUMNOS/ALUMNO[@id=\"" + Id + "\"]/estudios");

string Proyecto = "";

foreach(XmlElement ElementoProyecto in NodoEstudios)
{
    XmlNodeList EleProyecto = ElementoProyecto.GetElementsByTagName("proyecto");
    Proyecto = (EleProyecto[0] == null)?"": EleProyecto[0].InnerText;
}

Answer 4

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

Answer 5

//Check xml element value if exists using XmlReader

          using (XmlReader xmlReader = XmlReader.Create(new StringReader("XMLSTRING")))
           {

               if (xmlReader.ReadToFollowing("XMLNODE")) 

                {
                    string nodeValue = xmlReader.ReadElementString("XMLNODE");                
                }
            }     

Answer 6

Just came across the same problem and the null-coalescing operator with SelectSingleNode worked a treat, assigning null with string.Empty

 foreach (XmlNode txElement in txElements)
 {
     var txStatus = txElement.SelectSingleNode(".//ns:TxSts", nsmgr).InnerText ?? string.Empty;
     var endToEndId = txElement.SelectSingleNode(".//ns:OrgnlEndToEndId", nsmgr).InnerText ?? string.Empty;
     var paymentAmount = txElement.SelectSingleNode(".//ns:InstdAmt", nsmgr).InnerText ?? string.Empty;
     var paymentAmountCcy = txElement.SelectSingleNode(".//ns:InstdAmt", nsmgr).Attributes["Ccy"].Value ?? string.Empty;
     var clientId = txElement.SelectSingleNode(".//ns:OrgnlEndToEndId", nsmgr).InnerText ?? string.Empty;
     var bankSortCode = txElement.SelectSingleNode(".//ns:OrgnlEndToEndId", nsmgr).InnerText ?? string.Empty; 

     //TODO finish Object creation and Upsert DB
  }