Design Time integration

A DataSourceControl performs two main tasks at design time:

• Provide a configuration dialog to quickly configure the data source.
• Provide type schema information to the control using the data source in order to populate field pickers and to generate default templates based on the schema.
• The previous point forces us save the total row count to return it later, so the Select method could not be static.

The configuration wizard exposed by the CompatObjectDataSource is shown here:

The configuration wizard exposed by the ExtendedObjectDataSource is shown here:

As you can see the wizard lets us configure the methods called by data source controls in an easy way with just a few clicks and it also provides support to configure paging, sorting, filtering and optimistic concurrency.

The configuration wizard has an option to avoid persisting the paging, sorting and filtering parameters in the SelectParameters collection. This is because some times, those parameters are filled automatically by the control using the data source (for example, a GridView) and will be added automatically by the data source control when calling the SelectMethod. If you are using the CompatObjectDataSource, the SelectCountMethod will be called with the parameters persisted in the SelectParameters collection so if the paging parameters are persisted, the SelectCountMethod will need two parameters that probably it will not use. That's why there is an option to remove those parameters from the resulting collection.

The CompatObjectDataSource and the ExtendedObjectDataSource also provide type schema information to the controls using them as their data source. Because of that, the controls using those data sources can provide schema information and generate templates based on the schema information provided by the data source control as the next image shows: