Question

I have a problem with saving my data from TreeView. I’ve googled a lot of topics how to save data from TreeView to XML, and I saw i few methods how to make that. But all of them were using WindowsForms application, and nobody – WPF. I tried to convert those examples to WPF, but no one from them do not work correct. Is there any way to make it? One of the ways I tried to port:

    void SaveToXml(TreeView tw)
    {
        XmlDocument d = new XmlDocument();
        XmlNode n = d.CreateNode(XmlNodeType.Element, "root", "");
        foreach (TreeViewItem t in tw.Items)
        {
            n.AppendChild(getXmlNode(t, d));
        }
        d.AppendChild(n);
        d.Save(AppDomain.CurrentDomain.BaseDirectory + "out.xml");
    }
    private XmlNode getXmlNode(TreeViewItem tnode, XmlDocument d)
    {
        XmlNode n = d.CreateNode(XmlNodeType.Element, tnode.Name, " ");

        foreach (TreeViewItem t in tnode.Items)
        {
            n.AppendChild(getXmlNode(t, d));
        }
        return n;
    }

It throws ArgumentException “Local element’s and attribute’s names cannot be empty”. I’m trying to save info about files on my D:\ drive using code:

  private void ListDirectory(TreeView treeView, string path)
    {
        var rootDirectoryInfo = new DirectoryInfo(path);
        treeView.Items.Add(CreateDirectoryNode(rootDirectoryInfo));
    }

    private static TreeViewItem CreateDirectoryNode(DirectoryInfo directoryInfo)
    {
        var directoryNode = new TreeViewItem();
        directoryNode.Header = directoryInfo.Name;
        try
        {
            foreach (var directory in directoryInfo.GetDirectories())
                directoryNode.Items.Add(CreateDirectoryNode(directory));
            foreach (var file in directoryInfo.GetFiles())
                directoryNode.Items.Add(new TreeViewItem { Header = file.Name });
        }
        catch (UnauthorizedAccessException e)
        { }
        return directoryNode;
    }

It works fine, and TreeView shows all the folders and files. Please, show me how to save data from TreeView to XML. Thanks.

Tried this:

  public void exportToXml(TreeView tv, string filename)
    {
        sr = new StreamWriter(filename, false, System.Text.Encoding.UTF8);
        //Write the header
        sr.WriteLine("<?xml version=\"1.0\" encoding=\"utf-8\" ?>");
        //Write our root node
        sr.WriteLine("<ROOT>");
        foreach (TreeViewItem node in tv.Items)
        {
            saveNode(node.Items);
        }
        //Close the root node
        sr.WriteLine("</ROOT>");
        sr.Close();
    }

    private void saveNode(TreeViewItem[] tnc)
    {
        foreach (TreeViewItem node in tnc)
        {
            //If we have child nodes, we'll write 
            //a parent node, then iterrate through
            //the children
            if (node.Items.Count > 0)
            {
                sr.WriteLine("<" + node.Name + ">");
                saveNode(node.Items);
                sr.WriteLine("</" + node.Name + ">");
            }
            else //No child nodes, so we just write the text
                sr.WriteLine(node.Name);
        }
    }

But saveNode(node.Items); says that there are different types between node.Items and TreeViewItem[], so I tried List<TreeViewItem>, but error is the same.

Answer 1

I’m afraid this is not a real answer, but you may try replacing this line :

saveNode(node.Items); 

with this one :

saveNode(node.Items.OfType<TreeViewItem>().ToArray()); 

Hope this will help,

---

Example of getting an indented string from an xml doc :

public static String ToString(XmlDocument doc)
{
    StringBuilder sb = new StringBuilder();
    XmlTextWriter mywriter = new XmlTextWriter(new StringWriter(sb));
    mywriter.Formatting = Formatting.Indented;
    doc.WriteTo( mywriter );
    mywriter.Flush();
    return(sb.ToString());
}