Exposes a node of a hierarchical data structure, including the node object and some properties that describe characteristics of the node. Objects that implement the IHierarchyData interface can be contained in IHierarchicalEnumerable collections, and are used by ASP.NET site navigation and data source controls.
(in System.Web.dll)
Visual Basic (Declaration)
<AspNetHostingPermissionAttribute(SecurityAction.InheritanceDemand, Level := AspNetHostingPermissionLevel.Minimal)> _
<AspNetHostingPermissionAttribute(SecurityAction.LinkDemand, Level := AspNetHostingPermissionLevel.Minimal)> _
Public Interface IHierarchyData
Dim instance As IHierarchyData
[AspNetHostingPermissionAttribute(SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal)]
[AspNetHostingPermissionAttribute(SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
public interface IHierarchyData
[AspNetHostingPermissionAttribute(SecurityAction::InheritanceDemand, Level = AspNetHostingPermissionLevel::Minimal)]
[AspNetHostingPermissionAttribute(SecurityAction::LinkDemand, Level = AspNetHostingPermissionLevel::Minimal)]
public interface class IHierarchyData
public interface IHierarchyData
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.
Public Class FileSystemHierarchyData
Implements IHierarchyData
Public Sub New(ByVal obj As FileSystemInfo)
fileSystemObject = obj
End Sub
Private fileSystemObject As FileSystemInfo = Nothing
Public Overrides Function ToString() As String
Return fileSystemObject.Name
End Function
' IHierarchyData implementation.
Public Overridable ReadOnly Property HasChildren() As Boolean _
Implements IHierarchyData.HasChildren
Get
If GetType(DirectoryInfo) Is fileSystemObject.GetType() Then
Dim temp As DirectoryInfo = _
CType(fileSystemObject, DirectoryInfo)
Return temp.GetFileSystemInfos().Length > 0
Else
Return False
End If
End Get
End Property
' DirectoryInfo returns the OriginalPath, while FileInfo returns
' a fully qualified path.
Public Overridable ReadOnly Property Path() As String _
Implements IHierarchyData.Path
Get
Return fileSystemObject.ToString()
End Get
End Property
Public Overridable ReadOnly Property Item() As Object _
Implements IHierarchyData.Item
Get
Return fileSystemObject
End Get
End Property
Public Overridable ReadOnly Property Type() As String _
Implements IHierarchyData.Type
Get
Return "FileSystemData"
End Get
End Property
Public Overridable Function GetChildren() _
As IHierarchicalEnumerable _
Implements IHierarchyData.GetChildren
Dim children As New FileSystemHierarchicalEnumerable()
If GetType(DirectoryInfo) Is fileSystemObject.GetType() Then
Dim temp As DirectoryInfo = _
CType(fileSystemObject, DirectoryInfo)
Dim fsi As FileSystemInfo
For Each fsi In temp.GetFileSystemInfos()
children.Add(New FileSystemHierarchyData(fsi))
Next fsi
End If
Return children
End Function 'GetChildren
Public Overridable Function GetParent() As IHierarchyData _
Implements IHierarchyData.GetParent
Dim parentContainer As New FileSystemHierarchicalEnumerable()
If GetType(DirectoryInfo) Is fileSystemObject.GetType() Then
Dim temp As DirectoryInfo = _
CType(fileSystemObject, DirectoryInfo)
Return New FileSystemHierarchyData(temp.Parent)
ElseIf GetType(FileInfo) Is fileSystemObject.GetType() Then
Dim temp As FileInfo = CType(fileSystemObject, FileInfo)
Return New FileSystemHierarchyData(temp.Directory)
End If
' If FileSystemObj is any other kind of FileSystemInfo, ignore it.
Return Nothing
End Function 'GetParent
End Class 'FileSystemHierarchyData
public class FileSystemHierarchyData : IHierarchyData
{
private FileSystemInfo fileSystemObject = null;
public FileSystemHierarchyData(FileSystemInfo obj)
{
fileSystemObject = obj;
}
public override string ToString()
{
return fileSystemObject.Name;
}
// IHierarchyData implementation.
public bool HasChildren
{
get
{
if (typeof(DirectoryInfo) == fileSystemObject.GetType())
{
DirectoryInfo temp = (DirectoryInfo)fileSystemObject;
return (temp.GetFileSystemInfos().Length > 0);
}
else return false;
}
}
// DirectoryInfo returns the OriginalPath, while FileInfo returns
// a fully qualified path.
public string Path
{
get
{
return fileSystemObject.ToString();
}
}
public object Item
{
get
{
return fileSystemObject;
}
}
public string Type
{
get
{
return "FileSystemData";
}
}
public IHierarchicalEnumerable GetChildren()
{
FileSystemHierarchicalEnumerable children =
new FileSystemHierarchicalEnumerable();
if (typeof(DirectoryInfo) == fileSystemObject.GetType())
{
DirectoryInfo temp = (DirectoryInfo)fileSystemObject;
foreach (FileSystemInfo fsi in temp.GetFileSystemInfos())
{
children.Add(new FileSystemHierarchyData(fsi));
}
}
return children;
}
public IHierarchyData GetParent()
{
FileSystemHierarchicalEnumerable parentContainer =
new FileSystemHierarchicalEnumerable();
if (typeof(DirectoryInfo) == fileSystemObject.GetType())
{
DirectoryInfo temp = (DirectoryInfo)fileSystemObject;
return new FileSystemHierarchyData(temp.Parent);
}
else if (typeof(FileInfo) == fileSystemObject.GetType())
{
FileInfo temp = (FileInfo)fileSystemObject;
return new FileSystemHierarchyData(temp.Directory);
}
// If FileSystemObj is any other kind of FileSystemInfo, ignore it.
return null;
}
}
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="VB" AutoEventWireup="true" CodeFile="ihd_1.aspx.vb" Inherits="ihd_1_aspx" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html >
<head runat="server">
<title>Untitled Page</title>
</head>
<body>
<form id="form1" runat="server">
<div>
</div>
</form>
</body>
</html>
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="ihd_1.aspx.cs" Inherits="ihd_1_aspx" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html >
<head runat="server">
<title>Untitled Page</title>
</head>
<body>
<form id="form1" runat="server">
<div>
</div>
</form>
</body>
</html>
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
.NET Framework
Supported in: 3.5, 3.0, 2.0
Reference