The IHierarchicalEnumerable interface extends the IEnumerable interface and exposes GetHierarchyData, which is a method used to retrieve an IHierarchyData object from an enumerated item, in addition to the GetEnumerator method.

Typically, clients that use IHierarchicalEnumerable collections retrieve an IEnumerator object by calling the GetEnumerator method, then iterate through the enumeration and call the GetHierarchyData on each enumerated item to retrieve an IHierarchyData object.

The following code example demonstrates how to implement the IHierarchicalEnumerable interface with a class that extends ArrayList and provides a collection of IHierarchyData objects that wrap FileSystemInfo objects. The IHierarchicalEnumerable collection is used by classes that derive from HierarchicalDataSourceView to return a collection of hierarchical nodes when the Select method is called. This code example is part of a larger example provided for the HierarchicalDataSourceControl class.

' A collection of FileSystemHierarchyData objects

Public Class FileSystemHierarchicalEnumerable
   Inherits ArrayList
   Implements IHierarchicalEnumerable

   Public Sub New()
   End Sub 'New


   Public Overridable Function GetHierarchyData(enumeratedItem As Object) As IHierarchyData _
    Implements IHierarchicalEnumerable.GetHierarchyData
      Return CType(enumeratedItem, IHierarchyData)
   End Function 'GetHierarchyData

End Class 'FileSystemHierarchicalEnumerable

// A collection of FileSystemHierarchyData objects
public class FileSystemHierarchicalEnumerable : ArrayList, IHierarchicalEnumerable
{
    public FileSystemHierarchicalEnumerable () : base (){
    }

    public IHierarchyData GetHierarchyData(object enumeratedItem) {
        return enumeratedItem as IHierarchyData;
    }
}

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

.NET Framework

Reference