/// <summary>
/// Evaluates the XPath expression and returns the typed result.
/// </summary>
/// <param name="xpath">A string representing an XPath expression that can be evaluated.</param>
/// <returns></returns>
public object SelectXmlNodes(string xpath)
{
object retval = null;
// get the selected node
XPathNavigatorTreeNode node = this.SelectedNode as XPathNavigatorTreeNode;
// if there is no selected node, default to the root node
if (node == null && this.Nodes.Count > 0)
{
node = this.GetRootXmlTreeNode();
}
if (node == null)
{
return(null);
}
try
{
XPathExpression xpe = node.Navigator.Compile(xpath);
retval = node.Navigator.Evaluate(xpe);
}
catch (Exception ex)
{
ExpressionResultsWindow dialog = new ExpressionResultsWindow();
dialog.Expression = xpath;
dialog.Result = ex.Message;
dialog.ShowDialog(this.FindForm());
logger.Error(SQLSchemaTool.ERRORFORMAT, ex.Message, ex.Source, ex.StackTrace);
}
// evaluate the expression, return the result
return(retval);
}
/// <summary>
/// Loads an XPathNavigatorTreeNode for each XPathNavigator in the specified XPathNodeIterator, into the
/// specified TreeNodeCollection.
/// </summary>
/// <param name="iterator"></param>
/// <param name="treeNodeCollection"></param>
public virtual void LoadNodes(XPathNodeIterator iterator, TreeNodeCollection treeNodeCollection)
{
// handle null arguments
if (iterator == null)
{
throw new ArgumentNullException("navigator");
}
if (treeNodeCollection == null)
{
throw new ArgumentNullException("parentNodeCollection");
}
// use the wait cursor, in case this takes a while
this.UseWaitCursor = true;
try
{
treeNodeCollection.Clear();
// create and add a node for each navigator
foreach (XPathNavigator navigator in iterator)
{
XPathNavigatorTreeNode node = new XPathNavigatorTreeNode(navigator.Clone());
treeNodeCollection.Add(node);
}
}
finally
{
this.UseWaitCursor = false;
}
}
/// <summary>
/// Handles the expanding of an XPathNavigatorTreeNode.
/// </summary>
/// <param name="node"></param>
protected virtual void ExpandNode(XPathNavigatorTreeNode treeNode)
{
if (treeNode == null)
{
return;
}
// for better performance opening large files, tree nodes are loaded on demand.
// return if the node has already been expanded and loaded
if (treeNode.HasExpanded)
{
return;
}
// make sure we don't have to load this tree node again.
treeNode.HasExpanded = true;
this.BeginUpdate();
try
{
// load the child nodes of the specified xml tree node
this.LoadNodes(treeNode.Navigator.SelectChildren(XPathNodeType.All), treeNode.Nodes);
}
finally
{
this.EndUpdate();
}
}
/// <summary>
/// Finds a TreeNode for a given stack of XPathNavigators.
/// </summary>
/// <param name="ancestors">A Stack of XPathNavigators with which to find a TreeNode.</param>
/// <returns></returns>
private TreeNode GetXmlTreeNode(Stack <XPathNavigator> ancestors)
{
XPathNavigator navigator = null;
// start at the root
TreeNodeCollection nodes = this.Nodes;
TreeNode treeNode = null;
// loop through the ancestor XPathNavigators
while (ancestors.Count > 0 && (navigator = ancestors.Pop()) != null)
{
// loop through the TreeNodes at the current level
foreach (TreeNode node in nodes)
{
// make sure it's an XPathNavigatorTreeNode
XPathNavigatorTreeNode xmlTreeNode = node as XPathNavigatorTreeNode;
if (xmlTreeNode == null)
{
continue;
}
// check to see if we've found the correct TreeNode
if (xmlTreeNode.Navigator.IsSamePosition(navigator))
{
// expand the tree node, if it hasn't alreay been expanded
if (!node.IsExpanded)
{
node.Expand();
}
// we've taken another step towards the target node
treeNode = node;
// update the current level
nodes = node.Nodes;
// handle the next level, if any
break;
}
}
}
// return the result, if any was found
return(treeNode);
}
/// <summary>
/// Returns the root XPathNavigatorTreeNode in the tree.
/// </summary>
/// <returns></returns>
private XPathNavigatorTreeNode GetRootXmlTreeNode()
{
foreach (TreeNode node in this.Nodes)
{
XPathNavigatorTreeNode xmlTreeNode = node as XPathNavigatorTreeNode;
if (xmlTreeNode == null || xmlTreeNode.Navigator == null)
{
continue;
}
if (xmlTreeNode.Navigator.NodeType != XPathNodeType.Element)
{
continue;
}
return(xmlTreeNode);
}
return(this.Nodes[0] as XPathNavigatorTreeNode);
}
/// <summary>
/// Loads the initial xml tree node.
/// </summary>
protected virtual void Initialize()
{
XPathNavigatorTreeNode node = null;
// suspend drawing of the tree while loading nodes to improve performance
// as adding each node would normally require an entire redraw of the tree
base.BeginUpdate();
try
{
// clear all the nodes in the tree
base.Nodes.Clear();
// setting the navigator to null should just clear the tree
// no exception needs thrown
if (_navigator != null)
{
// if it's the root node of the document, load it's children
// we don't display the root
if (_navigator.NodeType == XPathNodeType.Root)
{
this.LoadNodes(_navigator.SelectChildren(XPathNodeType.Element), base.Nodes);
}
else
{
// otherwise, create a tree node and load it
node = new XPathNavigatorTreeNode(_navigator);
base.Nodes.Add(node);
}
}
}
finally
{
// resume drawing of the tree
base.EndUpdate();
if (node != null)
{
node.Expand();
}
}
}
protected override void OnBeforeExpand(TreeViewCancelEventArgs e)
{
XPathNavigatorTreeNode node = e.Node as XPathNavigatorTreeNode;
// expand the node, adding any child xml tree nodes
this.ExpandNode(node);
if (node != null)
{
if (node.Nodes.Count > 0)
{
TreeNodeCollection nodes = base.Nodes;
if (node.Parent != null)
{
nodes = node.Parent.Nodes;
}
// add a node for the xml end tag, such as </node>
node.Tag = nodes.Insert(e.Node.Index + 1, string.Format("</{0}>", node.Navigator.Name));
}
}
base.OnBeforeExpand(e);
}
/// <summary>
/// Loads the initial xml tree node.
/// </summary>
protected virtual void Initialize()
{
XPathNavigatorTreeNode node = null;
// suspend drawing of the tree while loading nodes to improve performance
// as adding each node would normally require an entire redraw of the tree
base.BeginUpdate();
try
{
// clear all the nodes in the tree
base.Nodes.Clear();
// setting the navigator to null should just clear the tree
// no exception needs thrown
if (_navigator != null)
{
// if it's the root node of the document, load it's children
// we don't display the root
if (_navigator.NodeType == XPathNodeType.Root)
{
this.LoadNodes(_navigator.SelectChildren(XPathNodeType.Element), base.Nodes);
}
else
{
// otherwise, create a tree node and load it
node = new XPathNavigatorTreeNode(_navigator);
base.Nodes.Add(node);
}
}
}
finally
{
// resume drawing of the tree
base.EndUpdate();
if (node != null)
{
node.Expand();
}
}
}
/// <summary>
/// Loads an XPathNavigatorTreeNode for each XPathNavigator in the specified XPathNodeIterator, into the
/// specified TreeNodeCollection.
/// </summary>
/// <param name="iterator"></param>
/// <param name="treeNodeCollection"></param>
public virtual void LoadNodes(XPathNodeIterator iterator, TreeNodeCollection treeNodeCollection)
{
// handle null arguments
if (iterator == null)
throw new ArgumentNullException("navigator");
if (treeNodeCollection == null)
throw new ArgumentNullException("parentNodeCollection");
// use the wait cursor, in case this takes a while
this.UseWaitCursor = true;
try
{
treeNodeCollection.Clear();
// create and add a node for each navigator
foreach (XPathNavigator navigator in iterator)
{
XPathNavigatorTreeNode node = new XPathNavigatorTreeNode(navigator.Clone());
treeNodeCollection.Add(node);
}
}
finally
{
this.UseWaitCursor = false;
}
}
/// <summary>
/// Handles the expanding of an XPathNavigatorTreeNode.
/// </summary>
/// <param name="node"></param>
protected virtual void ExpandNode(XPathNavigatorTreeNode treeNode)
{
if (treeNode == null)
return;
// for better performance opening large files, tree nodes are loaded on demand.
// return if the node has already been expanded and loaded
if (treeNode.HasExpanded)
return;
// make sure we don't have to load this tree node again.
treeNode.HasExpanded = true;
this.BeginUpdate();
try
{
// load the child nodes of the specified xml tree node
this.LoadNodes(treeNode.Navigator.SelectChildren(XPathNodeType.All), treeNode.Nodes);
}
finally
{
this.EndUpdate();
}
}
