Most users will send the Adaptable Blotter a datasource at start up and then allow users subsequently to filter and search on that data in the client using the various searching and filtering functions provided.
However, occasionally, your data source might be so big that you would like to provide an option for users to switch between different "data sources" so that the grid is populated with different data sets.
The DataSource Selector function allows you to do that. It simply provides a dropdown which contains a list of all the data sources that you provide it at design time through the DataSource section in your config. (See Data Source Config for more details).
These Data Sources are simply text names that you provide and will correspond to Stored Procedures or other server-related items that make sense to you.
When a Data Source is selected the Blotter will fire an event, providing the name of the newly selected Data Source and stating the trigger for the event to be 'DataSource'. (See Server Searching for more details).
AdaptableBlotter.JS will not perform any functionality itself when the Data Source - it will merely inform the user through an event and it is their responsibility to listen to the event and provide the Blotter with any data that has changed accordingly.
Typically when subscribing to this event, you will use the setGridData method in Grid API and set method in Layout API to provide the Blotter with the new Data and an appropriate Layout (see Blotter API for more details).