Export (0) Print
Expand All

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 class IHierarchicalDataSource

The IHierarchicalDataSource type exposes the following members.

Public methodGetHierarchicalViewGets the view helper object for the IHierarchicalDataSource interface for the specified path.

Public eventDataSourceChangedOccurs when the data storage that the IHierarchicalDataSource interface represents has changed.

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.

No code example is currently available or this language may not be supported.

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0
© 2015 Microsoft