How to show collapsible row in datagrid in WPF?

Question

How to show collapsible row in datagrid in WPF? I have 4 rows in a datagrid, and each row contains multiple rows, which means we can expand and collapse the main row.

Answer 1

Found the solution exactly what I want,

How to bind columns of a DataGrid in RowDetailsTemplate of another datagrid 

https://social.msdn.microsoft.com/Forums/vstudio/en-US/c9f5f168-b402-40aa-8505-b17bd18715f0/how-to-bind-columns-of-a-datagrid-in-rowdetailstemplate-of-another-datagrid?forum=wpf