Defines a provider interface for connecting two server controls using a single field of data.

See Also: IWebPartField Members


public interface IWebPartField


This interface is designed to be used with Web Parts connections. In a Web Parts connection, two server controls that reside in a System.Web.UI.WebControls.WebParts.WebPartZoneBase zone establish a connection and share data, with one control acting as the consumer and the other control acting as a provider. The mechanism for sharing data in a Web Parts connection is an interface instance, which the provider serves to the consumer by means of a callback method. To establish a connection, the consumer and provider must both work with the same interface type for sharing data. If the consumer does not recognize the interface type sent by the provider, it is still possible to connect the controls by means of a transformer (a System.Web.UI.WebControls.WebParts.WebPartTransformer object) that translates the interface instance sent by the provider into a type that the consumer recognizes. For details on connections, see System.Web.UI.WebControls.WebParts.WebPartConnection and Web Parts Connections Overview.

The System.Web.UI.WebControls.WebParts.IWebPartField interface is a provider interface included with the Web Parts control set as a standard interface for creating connections based on a data field. You can also create custom interfaces to use with Web Parts connections, but in many data-driven Web applications, it is useful to create connections based on a common row (for details, see the System.Web.UI.WebControls.WebParts.IWebPartRow interface), table (for details, see the System.Web.UI.WebControls.WebParts.IWebPartTable interface), or field from the data source, using the System.Web.UI.WebControls.WebParts.IWebPartField interface. In a typical connection, a System.Web.UI.WebControls.WebParts.WebPart control acting as a provider would implement the System.Web.UI.WebControls.WebParts.IWebPartField interface and provide an instance of the interface to consumers in a special callback method. For example, the provider might implement an System.Web.UI.WebControls.WebParts.IWebPartField interface for a field in your user information table that contains a Web user's postal code data. Another System.Web.UI.WebControls.WebParts.WebPart control acting as a consumer would define a special method to receive the interface instance, and could then extract the postal code data, and look up and display weather information based on the postal code.

The System.Web.UI.WebControls.WebParts.IWebPartField interface has two exposed members. The IWebPartField.Schema property returns schema information about the data field encapsulated in a System.ComponentModel.PropertyDescriptor object. The IWebPartField.GetFieldValue(FieldCallback) method declares a method that an implementer (such as a provider control) uses to retrieve the interface instance's field data when the callback method is invoked.


Namespace: System.Web.UI.WebControls.WebParts
Assembly: System.Web (in System.Web.dll)
Assembly Versions:
Since: .NET 2.0