XPath是XML的查询语言，其内容相当复杂。可以查阅www.w3.org/TR/xpath。
下面以一个实例简单了解一线XPath的查询方法：
public partial class Form1 : Form
{
private XmlDocument document;
public Form1()
{
InitializeComponent();
document = new XmlDocument();
FileStream fs = new FileStream("xmlFileSelect.xml", FileMode.Open, FileAccess.Read);
document.Load(fs);
this.Update(document.DocumentElement.SelectNodes("."));
}
private void Update(XmlNodeList nodes)
{
if (nodes == null || nodes.Count == 0)
{
textBox1.Text = "no result";
return;
}
string text = string.Empty;
foreach(XmlNode node in nodes)
{
textBox1.Text= Format(node, text, "");
}
}
private string Format(XmlNode node, string text, string indent)
{
if (node is XmlText)
{
text += node.Value;
return text;
}
if (string.IsNullOrEmpty(indent))
{
indent = "";
}
else
{
text += "
" + indent;
}
if (node is XmlComment)
{
text += node.OuterXml;
return text;
}
text += "<" + node.Name;
if (node.Attributes.Count > 0)
{
AddAttribute(node, ref text);
}
if (node.HasChildNodes)
{
text += ">";
foreach (XmlNode child in node.ChildNodes)
{
Format(child, text, indent + " ");
}
if (node.ChildNodes.Count == 1 && (node.FirstChild is XmlText || node.FirstChild is XmlComment))
{
text += "
" + indent + "</" + node.Name + ">";
}
}
else
{
text += "/>";
}
return text;
}
private void AddAttribute(XmlNode node, ref string text)
{
foreach (XmlAttribute attribute in node.Attributes)
{
text += " " + attribute.Name + "='" + attribute.Value + "'";
}
}
private void button1_Click(object sender, EventArgs e)
{
try
{
XmlNodeList nodes = document.DocumentElement.SelectNodes(textBox1.Text);
Update(nodes);
}
catch (Exception error)
{
textBox1.Text = error.ToString();
}
}
}
主要实现根据输入内容检索xmlnode