Is MoveToParent()/MoveToFirstChild() pair necessary with XPathNavigator? - c#

This is an example of using XPathNavigator from Microsoft.
using System;
using System.Xml;
using System.Xml.XPath;
// http://support.microsoft.com/kb/308343
namespace q308343 {
class Class1 {
static void Main(string[] args) {
XPathNavigator nav;
XPathDocument docNav;
docNav = new XPathDocument(#"Books.Xml");
nav = docNav.CreateNavigator();
nav.MoveToRoot();
//Move to the first child node (comment field).
nav.MoveToFirstChild();
do {
//Find the first element.
if (nav.NodeType == XPathNodeType.Element) {
//Determine whether children exist.
if (nav.HasChildren == true) {
//Move to the first child.
nav.MoveToFirstChild();
//Loop through all of the children.
do {
//Display the data.
Console.Write("The XML string for this child ");
Console.WriteLine("is '{0}'", nav.Value);
//Check for attributes.
if (nav.HasAttributes == true) {
Console.WriteLine("This node has attributes");
}
} while (nav.MoveToNext());
}
}
} while (nav.MoveToNext());
//Pause.
Console.ReadLine();
}
}
}
I think this code has a bug that it doesn't execute MoveToParent() to go up to one level when there is no elements to show.
nav.MoveToFirstChild();
//Loop through all of the children.
do {
....
} while (nav.MoveToNext());
nav.MoveToParent(); <-- This seems to be missing.
However, when I compile/execute this example, it works fine with and without nav.MoveToParent().
Is MoveToParent()/MoveToFirstChild() pair necessary with XPathNavigator? Is it OK not to use MoveToParent() because the second execution of MoveToNext() works as MoveToParent() when the first execution of MoveToNext() returns false?

In this code, after we go through all of the children of the root node, there is no more work to be done, there can't be more than one root node. So there is no need to MoveToParent(), we can just exit. Which is exactly what the code does.

Related

XMLNode. HasChild considers InnerText as a child node

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?
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");
}
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).

Accessing unknown child

In my code, I need to find a child of a child of a child.
Only the first child will always be the same child but the child of the child is randomized between 4 different possible prefabs.
on that last child I want to disable it's image.
here would be the ideal code if the child wouldn't be randomized between others:
protected void SetUnpickedPrizesVisibility(bool isVisible)
{
foreach (var element in list)
{
if (!element.IsPicked)
{ element.transform.FindChild("FirstChild").FindChild("SecondChild").FindChild("ThirdChild").GetComponent<Image>().enabled = false;
}
}
}
But since, the SecondChild varies, I can't simply do that.
Is my only option to do something like this?
protected void SetUnpickedPrizesVisibility(bool isVisible)
{
foreach (var element in list)
{
if (!element.IsPicked)
{
if(element.transform.FindChild("FirstChild").FindChild("SecondChild1"))
element.transform.FindChild("FirstChild").FindChild("SecondChild1").FindChild("ThirdChild").GetComponent<Image>().enabled = false;
if(element.transform.FindChild("FirstChild").FindChild("SecondChild2"))
element.transform.FindChild("FirstChild").FindChild("SecondChild2").FindChild("ThirdChild").GetComponent<Image>().enabled = false;
if(element.transform.FindChild("FirstChild").FindChild("SecondChild3"))
element.transform.FindChild("FirstChild").FindChild("SecondChild3").FindChild("ThirdChild").GetComponent<Image>().enabled = false;
}
}
}
Or does someone have a different idea?
I know this is a very confusing to read question but I tried my best to simplify it.
Thanks,
So why not add a script to the prefab of the last child that disables the image. That way you only need to keep a reference to the script when you instantiate it and not go looking for the children.
You can just search through, something like this:
foreach (var element in list)
{
if (!element.IsPicked)
{
foreach(var grandChild in element)
{
foreach(var greatGrandChild in grandChild)
{
greatGrandChild.GetComponent<Image>().enabled = false;
}
}
}
}
It's easier to use child, grandChild and greatGrandChild rather than child of the child of child :-)

how to assign image for Parent node and child nodes in treeview from assigned imagelist in c#?

I have a TreeView and an associated ImageList. What are the steps to add images to the Parent and child nodes ?
All the nodes are being added from the code. Nothing is done from the Design.
public void fill_tree()
{
host_listbox_new.Items.Clear();
foreach (KeyValuePair<string, host_config> hlitem in host_list)
{
string sitem = hlitem.Key;
if (host_list[sitem].sessionOptions == null)
host_list[sitem].sessionOptions = new SessionOptions();
host_list[sitem].sessionOptions.Protocol = Protocol.Sftp;
host_list[sitem].sessionOptions.HostName = host_list[sitem].ip;
host_list[sitem].sessionOptions.UserName = host_list[sitem].username;
host_list[sitem].sessionOptions.Password = host_list[sitem].password;
host_list[sitem].sessionOptions.PortNumber = Convert.ToInt32(host_list[sitem].port);
//host_list[sitem].sessionOptions.SshHostKeyFingerprint = host_list[sitem].rsa;
if (treeView1.SelectedNode != null)
{
treeView1.SelectedNode.Nodes.Add(hlitem.Key.ToString());
}
else
{
treeView1.Nodes[0].Nodes.Add(hlitem.Key.ToString());
}
}
}
private void Parent_Load(object sender, EventArgs e)
{
read_process_config();
read_host_config();
host_listbox.Items.Clear();
treeView1.BeginUpdate();
treeView1.Nodes.Add("Servers");
fill_tree();
treeView1.EndUpdate();
treeView1.ExpandAll();
connect_server_bttn.Enabled = false;
}
i want to add items i.e child nodes to Server Parent node each of them having one image before them ( green image if hlitem.Value.connected is true. red image if hlitem.Value.connected is false)
But i have no idea about treeview or imagelist.
Can anyone help me about the whole thing?
The Add command returns a reference to the new Node. You can use it to style the Node.
Change your code to this:
if (treeView1.SelectedNode != null)
{
TreeNode tn =treeView1.SelectedNode.Nodes.Add(hlitem.Key.ToString());
tn.ImageIndex = yourIndex;
}
else
{
TreeNode tn =treeView1.Nodes[0].Nodes.Add(hlitem.Key.ToString());
tn.ImageIndex = yourIndex;
}
Or whatever logic you need to set the index.
If you need the parent node's index you could write:
tn.ImageIndex = tn.Parent.ImageIndex;
You may also want ot check out the other formats of the Add method. Some let you include the ImageIndex directly. You can also include the SelectedIndex; especially if you don't want that you should include it to prevent the Tree using its default SelectedIndex!
This will set the node to show the 2nd image, whether selected or not:
TreeNode tn =treeView1.Nodes[0].Nodes.Add(sitem, sitem, 1,1 );
Since you can't set a property of an object before you have created it, you can't set the Child nodes when you create the parent node. Instead you can use a simple function to do the changes:
void copyImgIndexToChildren(TreeNode tn)
{
if (tn.Nodes.Count > 0)
foreach (TreeNode cn in tn.Nodes) cn.ImageIndex = tn.ImageIndex;
}
void copyImgIndexToAllChildren(TreeNode tn)
{
if (tn.Nodes.Count > 0)
foreach (TreeNode cn in tn.Nodes)
{
cn.ImageIndex = tn.ImageIndex;
copyImgIndexToAllChildren(cn);
}
}
The first method changes the direct ChildNodes only , the 2nd recursively changes all levels below the starting node.
BTW: Is there a reason to use hlitem.Key.ToString() in your code instead of sitem?

Why are my child nodes not detected without the parent node being selected?

I have a treelist in my form with checkboxes enabled. I need to add anything checked to a list so I can write that list out. If I check any parent nodes (or highest level nodes) it includes them. If I select any parent nodes it also selects its children nodes (this is intentional), and displays those. But If I check any child nodes only, it won't add them to my list.
//check to see if there are any nodes checked
bool nodeHasCheck = false;
foreach (TreeNode n in nodes)
{
if (n.Checked)
{
nodeHasCheck = true;
break;
}
GetExtendedFeatures(n.Nodes);
}
//only return stuff if something's checked
if (nodeHasCheck == true)
{
foreach (TreeNode n in nodes)
{
if (n.Checked)
{
//n.BackColor = Color.Black;
nodeList.Add(n.Text);
}
GetExtendedFeatures(n.Nodes);
}
It also appears that if I select 2 parent nodes, the recursion that occurs (Think that's the right term) is causing it to find the first checked node, then starts over, and adds that same checked node a second time before it hits the second set of nodes.
I provided my node test, hopefully it's enough to identify why it's not detecting child nodes selected without the parent node selected.
UPDATED - 3/18/13
My button click code:
private void btnGenerate_Click(object sender, EventArgs e)
{
ScanNodes(treeView1.Nodes[0]);
}
private void ScanNodes(TreeNode parent)
{
foreach (TreeNode node in parent.Nodes)
{
if (node.Checked)
{
nodeList.Add(node.Text.ToString());
}
if (node.Nodes.Count > 0)
{
ScanNodes(node);
}
}
var message = string.Join(Environment.NewLine, nodeList);
message = message.Replace(Environment.NewLine, ", ");
MessageBox.Show(message);
nodeList.Clear();
}
To get a List of all the selected nodes in a TreeView you can use the following:
Supose the list is named nodeList:
//We First declare a recursive method to loop through all nodes,
//we need to pass a root node to start
private void ScanNodes(TreeNode parent)
{
foreach (TreeNode node in parent.Nodes)
{
if (node.Checked)
{
nodeList.Add(node.Text);
}
if (node.Nodes.Count > 0)
{
ScanNodes(node);
}
}
}
With that set up You just need to call the ScanNodes method and pass the root node of your TreeView:
ScanNodes(treeView1.Nodes[0]);
Regards,

Sharepoint 2010 - webpart treeview is not working

Hi I am using sharepoint 2010 and am creating a tree view in a webpart to display items from a document library. This code isn't working for me, its displaying everything in the same web...
I would like to be able to specify which document library to use.
Also it puts in duplicate nodes in, so if I go to editpage, it adds a duplicate, if I leave edit mode it adds another duplicate.
Can anyone help?
using System;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using Microsoft.SharePoint;
using Microsoft.SharePoint.Utilities;
using System.Web;
using System.IO;
namespace VisualWebPartProject1.VisualWebPart1
{
public partial class VisualWebPart1UserControl : UserControl
{
protected void Page_Load(object sender, EventArgs e)
{
SPWeb thisWeb = null;
TreeNode node;
using (thisWeb = SPContext.Current.Web)
{
//Add the Web's title as the display text for the tree node, and add the URL as the NavigateUri.
node = new TreeNode(thisWeb.Title, null, null, thisWeb.Url, "_self");
//The Visual Web Part has a treeview control called siteStructure.
siteStructure.Nodes.Add(node);
//Get a reference to the current node, so child nodes can be added in the correct position.
TreeNode parentNode = node;
//Iterate through the Lists collection of the Web.
/*
foreach (SPListItem item in myList.Items)
{
SPFieldUrlValue data = item["Url"] as SPFieldUrlValue;
// now you have data.Description, data.Url
node = new TreeNode(Path.GetFileName(data.Url), null, null, data.Url, "_self");
parentNode.ChildNodes.Add(node);
}
*/
foreach (SPList list in thisWeb.Lists)
{
if (!list.Hidden)
{
node = new TreeNode(list.Title, null, null, list.DefaultViewUrl, "_self");
parentNode.ChildNodes.Add(node);
}
}
foreach (SPWeb childWeb in thisWeb.Webs)
{
//Call our own helper function for adding each child Web to the tree.
addWebs(childWeb, parentNode);
childWeb.Dispose();
}
siteStructure.CollapseAll();
}
}
void addWebs(SPWeb web, TreeNode parentNode)
{
TreeNode node;
node = new TreeNode(web.Title, null, null, web.Url, "_self");
parentNode.ChildNodes.Add(node);
parentNode = node;
foreach (SPList list in web.Lists)
{
if (!list.Hidden)
{
node = new TreeNode(list.Title, null, null, list.DefaultViewUrl, "_self");
parentNode.ChildNodes.Add(node);
}
}
foreach (SPWeb childWeb in web.Webs)
{
//Call the addWebs() function from itself (i.e. recursively)
//to add all child Webs until there are no more to add.
addWebs(childWeb, parentNode);
childWeb.Dispose();
}
}
}
}
Try adding this before your using statement:
If(node.Nodes.Count == 0) { // The rest of your code here }
Add WebProperties to your WebPart to be able to configure for example the Library which you would like to use instead a hardcoded one. In this Property you could specify the Lists Name and read it to load this list.
Also to avoid multiple inserts on edit, etc. please add your code inside the Page_Load Event inside
if (!Page.IsPostBack)
{
Your code goes here...
}
This avoids the execution of your code everytime you load or even postback the page and this causes that you add each time a new node to your tree.

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