Disabling XML DataSources
In WSS object model, there is a family of XML-based data source controls which enable declarative or programmatic databinding models against a variety of underlying XML data stores. In this family, the abstract BaseXmlDataSource control serves as the base class .It extends HierarchicalDataSourceControl class and implements IDataSource interface to support both hierarchical and tabular data for all derived types. There are three main XML-based data sources that extend BaseXmlDataSource control :
*Read the community content in each class for more information.
For example, if you place a RSS Viewer Web Part on a page and sets its RSS Feed URL property , open the page in SharePoint Designer and you would see that XmlUrlDataSource is used as the main data source serving the Web part.
Browse to Central Administration Web site , Operations tab and choose Data Retrieval Service link in the Data Configuration section. As you can see on the bottom of this page, there is a checkbox by which you can enable/disable XmlUrlDataSource, SPXmlDataSource, SoapDataSource or AggregateDataSource data source controls per Web application or globally across the entire farm. Once “Enable these data source controls” check box is cleared , no query requests will be processed by these data source controls. This is a great controling and performace check feature in the hands of administrators to control databinding operations in a SharePoint Web application.
Clear the checkbox and do an iisreset. Then referesh the page containing the RSS Viewer web part and as expected , you will get the following error message.
Check the ULS log and here is the execption thrown by the RSS Viewer Web Part. One of a few pleasant error messages , eh? 😉
RssWebPart: Exception handed to HandleRuntimeException.HandleException Microsoft.SharePoint.WebPartPages.DataSourceControlDisabledException: The server administrator has disabled the Data Source control required to execute this query. Contact the server administrator for more information.
