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IHierarchicalDataSource Interface

Represents a hierarchical data source that hierarchical data-bound controls such as TreeView can bind to.

Namespace:  System.Web.UI
Assembly:  System.Web (in System.Web.dll)

public interface IHierarchicalDataSource

The IHierarchicalDataSource type exposes the following members.

  NameDescription
Public methodGetHierarchicalViewGets the view helper object for the IHierarchicalDataSource interface for the specified path.
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  NameDescription
Public eventDataSourceChangedOccurs when the data storage that the IHierarchicalDataSource interface represents has changed.
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ASP.NET supports a control data-binding architecture that enables Web server controls to bind to data and present it in a consistent fashion. Web server controls that bind to data are called data-bound controls, and the classes that facilitate binding are called data source controls. Data source controls can represent any data source: a file, a stream, a relational database, a business object, and so on. Data source controls present data in a consistent way to data-bound controls, regardless of the source or format of the underlying data.

Data source controls that represent hierarchical data derive from the HierarchicalDataSourceControl class, which is the base ASP.NET implementation of the IHierarchicalDataSource interface. The IHierarchicalDataSource interface is used to define data source controls that expose hierarchical data, rather than tabular or list-style data, to Web server controls that derive from the HierarchicalDataBoundControl class, such as the TreeView control. The interface defines a single method, GetHierarchicalView, which retrieves a strongly typed HierarchicalDataSourceView object. Data source controls that implement this interface support a hierarchical view for each hierarchical level of data they represent. The data source views are not named, like DataSourceView objects, but are identified by their unique hierarchical path, which is the viewPath parameter passed to the GetHierarchicalView method.

You can think of a data source control as the combination of the IHierarchicalDataSource object and its associated views on the underlying data. Each associated HierarchicalDataSourceView object defines the capabilities of a data source control for the hierarchical level represented, and, like all ASP.NET data source view objects, performs operations such as insert, update, delete, and sort.

Data source controls that expose only hierarchical data, such as SiteMapDataSource, are derived from the HierarchicalDataSourceControl class. Other data source controls that expose their data as both hierarchical data and tabular data, such as XmlDataSource, are derived from HierarchicalDataSourceControl but implement the IDataSource and IListSource interfaces.

The following code example demonstrates how to extend the abstract HierarchicalDataSourceControl class, which implements the IHierarchicalDataSource interface, to create a data source control that displays file system information. The FileSystemDataSource class provides an implementation of the GetHierarchicalView method, which retrieves a strongly typed view object for a specified file system path. This code example is part of a larger example provided for the HierarchicalDataSourceControl class.


using System;
using System.Collections;
using System.IO;
using System.Runtime.InteropServices;
using System.Security.Permissions;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public class FileSystemDataSource :
    HierarchicalDataSourceControl, IHierarchicalDataSource
{
    private FileSystemDataSourceView view = null;

    public FileSystemDataSource() : base() { }

    protected override HierarchicalDataSourceView
        GetHierarchicalView(string viewPath)
    {
        view = new FileSystemDataSourceView(viewPath);
        return view;
    }
}


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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