XMLNode. HasChild considers InnerText as a child node

Question

I’m working on a windows form application I’m trying to see if a certain xml node has child nodes, in the first lines of my code I used OpenFileDialog to open an xml file; in this case the xml sample below.

<bookstore>
   <book category="cooking">
     <title lang="en">Everyday Italian</title>
     <author>Giada De Laurentiis</author>
     <year>2005</year>
     <price>30.00</price>
   </book>
</bookstore>

In my windows form application, I have an open button and a textbox1, the textbox1 is only used to display the address of the xml file and the open button sets everything in motion. Somewhere in the code I have the following lines of code:

using System;
using System.Data;
using System.Windows.Forms;
using System.Xml;
using System.IO;

//other lines of code
private void Open_XML_button_Click(object sender, EventArgs e)
{
//other lines of code
XmlDocument xmldoc = new XmlDocument();
string XML_Location;

XML_Location = textBox1.Text;
xmldoc.Load(XML_Location);

string category = "category = 'cooking'";
XmlNode test1 = xmldoc.SelectSingleNode(string.Format("/bookstore/book[@{0}]/author", category));

if (test1.HasChildNodes == true)
                        {
                            MessageBox.Show("It has Child nodes");
                        }

                        else
                        {
                            MessageBox.Show("it does not have Child nodes");
                        }
}

Here is what I don’t understand, I’m pointing to the author node which, as far as I can tell, does not have a child node but my code states that it does; if I were to erased Giada de Laurentiis then my code would say that the author node does not have

What Am I doing wrong?

score 4 · Accepted Answer · answered Feb 16 '17 at 21:36

4

You could check whether there are any child nodes that don't have a NodeType of XmlNodeType.Text:

string category = "category = 'cooking'";
XmlNode test1 = xmldoc.SelectSingleNode(string.Format("/bookstore/book[@{0}]/author", category));
if (test1.ChildNodes.OfType<XmlNode>().Any(x => x.NodeType != XmlNodeType.Text))
{
    MessageBox.Show("It has Child nodes");
}
else
{
    MessageBox.Show("it does not have Child nodes");
}

answered Feb 16 '17 at 21:36

mm8

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I'm happy to say the code works now with the changes you make to it, one last thing what is `x => x.NodeType != XmlNodeType.Text` doing? is that the lambda operator/expression? – R. Ben Feb 17 '17 at 13:50
Yes, it is a Predicate delegate represented by a lambda expression that filters the ChildNodes collection based on the NodeType: https://msdn.microsoft.com/en-us/library/bfcke1bz(v=vs.110).aspx – mm8 Feb 17 '17 at 14:13

score 0 · Answer 2 · answered Feb 16 '17 at 20:47

It has a child node which is an instance of https://msdn.microsoft.com/en-us/library/system.xml.xmltext(v=vs.110).aspx XmlText. In the DOM there are different kind of nodes and the property HasChildNodes checks for any kind of child nodes (element, comment, processing instruction, text, cdata).

XMLNode. HasChild considers InnerText as a child node

2 Answers2