如何使用XDocument将指定XML结构展示为TreeView？

Absolutely—XDocument (from LINQ to XML) is an excellent, modern choice for this task, and it’s generally preferred over the older XmlDocument API for most XML parsing scenarios in .NET. Here’s why, plus a practical implementation example:

Why XDocument is a great fit #

• LINQ-friendly: You can use LINQ queries to easily traverse and filter XML nodes, making the TreeView population logic more intuitive and concise.
• Clean, readable syntax: XDocument uses a fluent API that cuts down on boilerplate code compared to XmlDocument, making your code easier to maintain.
• Memory-efficient: It loads the XML into an in-memory tree structure that’s straightforward to navigate and manipulate.
• Full support for modern XML features: Handles namespaces, mixed content, and complex element structures seamlessly—even elements with spaces in their names (like your <Level 1> nodes) work without issue.

Example Implementation (C# WinForms) #

Let’s walk through loading your XML and building the TreeView:

First, load the XML into an XDocument (you can parse a string or load directly from a file):

string xmlContent = @"<?xml version=""1.0"" encoding=""utf-8""?>
<rootnode>
  <Level 1>
    <Level 2>
      <Level 3> </Level 3>
    </Level 2>
    <Level 2>
      <Level 3> </Level 3>
    </Level 2>
  </Level 1>
  <Level 1>
    <Level 2>
      <Level 3> </Level 3>
    </Level 2>
  </Level 1>
</rootnode>";

XDocument doc = XDocument.Parse(xmlContent);
// Or load from a file: XDocument.Load("your-xml-file.xml");

Next, create a recursive method to build TreeView nodes from XML elements:

private void AddXmlNodesToTree(XElement xmlElement, TreeNode parentTreeNode)
{
    // Create a new TreeNode for the current XML element
    TreeNode currentNode = new TreeNode(xmlElement.Name.LocalName);
    parentTreeNode.Nodes.Add(currentNode);

    // Recursively add child elements
    foreach (XElement childElement in xmlElement.Elements())
    {
        AddXmlNodesToTree(childElement, currentNode);
    }
}

Finally, initialize the TreeView with your XML structure:

// Clear existing nodes first
treeView1.Nodes.Clear();

// Start with the root XML element
XElement rootElement = doc.Root;
if (rootElement != null)
{
    TreeNode rootTreeNode = new TreeNode(rootElement.Name.LocalName);
    treeView1.Nodes.Add(rootTreeNode);
    
    // Add all child elements under the root
    foreach (XElement childElement in rootElement.Elements())
    {
        AddXmlNodesToTree(childElement, rootTreeNode);
    }
}

// Expand all nodes to show the full structure
treeView1.ExpandAll();

Quick Notes #

• If you’re working with WPF instead of WinForms, the logic is nearly identical—just replace TreeNode with TreeViewItem and adjust the UI initialization code slightly.
• For extremely large XML files (gigabytes in size), consider using XmlReader for streaming to avoid loading the entire document into memory. But for scenarios like your example, XDocument is perfect.

Content of the question originates from Stack Exchange, asked by Hubii