Master-Detail Grid is a use case scenario, in which the details of a Master Grid record, is viewed in a separate Grid(Detail Grid) by clicking the particular row.
The steps to achieve this scenario is as follows,
                        rowSelected
                     event.
                        dataSource
                     property.The above demo is implemented as follows.
DetailComponent(ej-griddetail) to show details of selected row from Master Grid.DetailComponent has an Input property key, based on which
                        the data will be filtered and set to the Detail Grid. Here the CustomerID value is used as key value.MasterComponent which has Master Grid component with 
                        rowSelected
                     event bound to it.MasterComponent uses DetailComponent and it updates key property when a row is selected in the Master Grid.Use 
                    selectedRowIndex
                 to select a row at the initial rendering.
Injecting Module
                    Grid component features are segregated into individual feature-wise modules. To implement this use case,
                    the selection feature need to be enabled and also we need to inject
                    Selection module into the services.