Question

I have a simple XML doc with no Namespace

Here is the code I wrote in C# to search for a particular element based on Name.

public XmlElement SearchXML(string name)
    {
    XmlDocument xDoc = new XmlDocument();
    string filePath = ConfigurationManager.AppSettings["path"];
    xDoc.Load(filePath);

        string xQryStr = "//NewPatient[Name='" + name + "']";
        xDoc.SelectNodes(xQryStr);

        XmlElement xmlEle = xDoc.DocumentElement;
        return xmlEle;
    }

The XML document is as follows

When I try to call the method SearchXML and pass Dennis as the arguement, instead of returning the xml element containing only the specific elements, it returns the entire document.

Where am I possibly erring?

Any help appreciated.

Answer 1

If you want to select a list of nodes based on an XPath expression, you need to use .SelectNodes in this fashion:

public XmlElement SearchXML(string name)
{
    XmlDocument xDoc = new XmlDocument();
    string filePath = ConfigurationManager.AppSettings["path"];
    xDoc.Load(filePath);

    string xQryStr = "//NewPatient[Name='" + name + "']";

    XmlNodeList listOfNodes = xDoc.SelectNodes(xQryStr);

    foreach(XmlNode node in listOfNodes
    {
       // do something with that list of XML nodes you've selected....
       // XmlElement xmlEle = node;
       // return xmlEle;
    }
}

The call to .SelectNodes(xpath) returns a list of matching XML nodes (see the MSDN documentation on XmlDocument.SelectNodes) – once you have that list, you can iterate over the matched nodes and do something with them….

Or if you’re expecting only a single XML node to match your XPath expression, you can use .SelectSingleNode, too:

    string xQryStr = "//NewPatient[Name='" + name + "']";

    XmlNode matchedNode = xDoc.SelectSingleNode(xQryStr);

    if(matchedNode != null)
    {
       // do something with that list of XML nodes you've selected....
       return matchedNode;
    }