IHierarchyData Interface
Assembly: System.Web (in system.web.dll)
The IHierarchyData interface is implemented by classes that represent nodes of a hierarchical structure, and track the hierarchical relationships to their parent and child nodes. Classes that implement the IHierarchyData interface can be contained in collections that implement the IHierarchicalEnumerable interface.
The following code example demonstrates how to implement the IHierarchyData interface with a class that wraps a FileSystemInfo object. The FileSystemInfo class is a good example of a hierarchical data node, which the IHierarchyData interface represents for ASP.NET hierarchical data source controls. This code example is part of a larger example provided for the HierarchicalDataSourceControl class.
The following code example demonstrates how to recursively iterate through an IHierarchicalEnumerable collection, extract the IHierarchyData item from the enumerator using the GetHierarchyData method, and perform basic work with the data item.
<%@ Page Language="VJ#"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
private void Page_Load(Object sender, System.EventArgs e)
{
IHierarchicalEnumerable ihe =
(IHierarchicalEnumerable)SiteMap.get_RootNode().get_ChildNodes();
IEnumerator enumeration = ihe.GetEnumerator();
while (enumeration.MoveNext()) {
// Print out SiteMapNode Titles.
IHierarchyData hierarchicalNode =
ihe.GetHierarchyData(enumeration.get_Current());
PrintFullChildNodeInfo(hierarchicalNode);
}
}//Page_Load
// Print out the the current data node, then iterate through its
// children and do the same.
private void PrintFullChildNodeInfo(IHierarchyData node)
{
String whitespace = " ";
String br = "<br />";
get_Response().Write(node.toString() + br);
get_Response().Write(whitespace + node.get_Path() + br);
// Check for specific types and perform extended functions.
if (node.get_Type().Equals("SiteMapNode")) {
// Because SiteMapNode implements the IHierarchyData interface,
// the IHierarchyData object can be cast directly as a SiteMapNode,
// rather than accessing the Item property for the object that
// the Type property identifies.
SiteMapNode siteNode = null;
siteNode = (SiteMapNode)node.get_Item();
get_Response().Write(whitespace + siteNode.get_Url() + br);
get_Response().Write(whitespace + siteNode.get_Description() + br);
}
else {
if (node.get_Type().Equals("SomeBusinessObject")) {
// If the IHierarchyData instance is a wrapper class on a
// business object of some kind, you can retrieve the business
// object by using the IHierarchyData.Item property.
// SomeBusinessObject busObj = node.Item as SomeBusinessObject;
}
}
if (node.get_HasChildren()) {
IEnumerator children =
((IHierarchicalEnumerable)node.GetChildren()).GetEnumerator();
while (children.MoveNext()) {
// Print out SiteMapNode Titles recursively.
IHierarchyData hierarchicalNode =
node.GetChildren().GetHierarchyData(children.get_Current());
PrintFullChildNodeInfo(hierarchicalNode);
}
}
}//PrintFullChildNodeInfo
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>ASP.NET Example</title>
</head>
<body>
<form id="form1" runat="server">
</form>
</body>
</html>