Mapping TreeView to/from xmldoc

Question

Hi Developing a trad win app using VS 2010 C#. Starting from loading a xml file into a XMLDocument object. openedFile = someFile.xml; xmlReader = new XmlTextReader(openedFile); Global.mainXMLDoc.Load(xmlReader); xmlReader.Close(); private void AddNodeToTreeView(ref XmlNode inXmlNode ref TreeNode inTreeNode) { XmlNode xNode; TreeNode tNode; XmlNodeList nodeList; if (inXmlNode.HasChildNodes) { nodeList = inXmlNode.ChildNodes; for (int i = 0; i { xNode = inXmlNode.ChildNodes[i]; inTreeNode.Nodes.Add(new TreeNode(xNode.Name)); tNode = inTreeNode.Nodes[i]; AddNodeToTreeView(ref xNode ref tNode); } } } Now I have a multi column ListView to show the attributes whenever user selects a node from the TreeView component. Here's where it all gets totally wrong. My first idea was to use the tv.SelectedNode.Index (in the TreeView event listener _AfterSelect). But since this index is calculated relatively its parent the mapping to the xmlNodes is lost. private void treeView_AfterSelect(object sender TreeViewEventArgs e TreeView tv ListView lv) { lv.Items.Clear(); ListViewItem lvItem; currentNodeName = tv.SelectedNode.Text; int currentNodeIx = tv.SelectedNode.Index; xmlNodes = Global.mainXMLDoc.GetElementsByTagName(currentNodeName); XmlNode xNode = xmlNodes.Item(currentNodeIx); string attr; string val; for (int i = 0; i { attr = xNode.Attributes[i].Name; val = xNode.Attributes[i].Value; lvItem = new ListViewItem(attr); string foo = FindXPath(xNode.Attributes[i]); lvItem.SubItems.Add(val); lvItem.SubItems.Add(foo); lv.Items.Add(lvItem); } } So is there a way you can do this using these standard components or do I need to design my own? Cheers!

Sam Hobbs · Answer

The hash code is not designed for that. The Tag property is designed to do what you need. Please don't be so quick to conclude it won't help. There is one thing that should be mentioned but you only need to look at the documentation to understand this. The Tag property can be any object; it does not need to be a string. So the Tag can be set to a XmlNode. A more advanced solution would be to derive a class from TreeNode and then you could put whatever you needed to in that class. Then whenever you had a TreeNode you would have the additional members too.

Peer · Answer

Here's the exact code (attached because I couldn't copy and paste to here???)

Sam Hobbs · Answer

I am not sure how you are using the hash code. I am assuming it is more work to do than using the Tag.

Peer · Answer

Ok sorry I didn't mean to ignore your solution but I had tried using the Tag by assigning it to a unique counter. Now that did not help me (of course not since a counter won't be a suitable datatype at all for this problem). I did realize that the Tag datatype is OBJECT i.e. a very general type but I didn't think as far as you did so thanks I will assign it to the xmlNode itself and that should do it. However so far my HashCode idea IS working or am I wrong again? so changing this to your solution might not be necessary even though that should be a more correct way of doing it. Thanks!

Peer · Answer

Thanks but I don't see how setting the Tag property of each added TreeNode is helping me mapping back to the underlying xml? The TreeNode.Text in my app would get the value from a specific node in my xml. Now what I want is when selecting this TreeNode I need to know what xml node this was generated from. Anyway I think I might have come up with a solution: By using the HashCode in the xml. This should give me an unique identifier for each node I add.

Frogleg · Answer

Look here namespace treeNodes { public partial class Form1 : Form { TreeNode rootNode sub1Node sub2Node; public Form1() { InitializeComponent(); } private void Form1_Load(object sender EventArgs e) { } private void button1_Click(object sender EventArgs e) { rootNode = treeView1.Nodes.Add(RootNode); rootNode.Tag = (Xml one); rootNode.Text = (Xml one too); sub1Node = rootNode.Nodes.Add(sub1Node); sub1Node.Tag = (Xml two); sub1Node.Text = (Xml two too); sub2Node = sub1Node.Nodes.Add(sub2Node); sub2Node.Tag = (Xml three); sub2Node.Text = (Xml three too); } private void treeView1_AfterSelect(object sender TreeViewEventArgs e) { MessageBox.Show(treeView1.SelectedNode.Tag.ToString() +   + treeView1.SelectedNode.Text); } private void treeView1_BeforeExpand(object sender TreeViewCancelEventArgs e) { } } }

Peer · Answer

Well I don't know about deep waters I thought that this question was rather straight forward when asked in an Expert forum like yours? Yes. I think I can try to summarize it in plain English. I populate a TreeView component with data from a xml which is no problem even though you'll have write your own recursive routine to do this. Later on when I want to use the data in the TreeView to fill a ListView component with the attributes of the node in TreeView that the user clicked there's no mapping BACK to the xml (I'm using a XML Document MS construct to store the data in cache). I've tried to solve this by using the e.node.index (e = event arg from TreeView) but this index won't be the correct one. So my question is simply how can I preserv the connection between TreeView and XML so that I can mapp between these components in any direction? Clear enough?

Sam Hobbs · Answer

Deer Peer (I am sure you have heard that before). You sure chose to jump right into deep waters. I get the impression that people don't want to study all that code. Can you try to describe what you need to do? Instead of just showing code. Try to make it interesting; avoid many details. The more interesting it is to read the more likely you will get help.