I have a datagrid with a sub-datagrid where the data of the sub-datagrid are displayed when I click on one of the main lines datagrid (Figure 1).
When I change (for example) the type of document to consult, the application has to re-record the data from datagrid and sub-datagrid.
Then gives the error "NullReferenceException was unhandled".
I'm using the same instructions I use with a simple datagrid and can not correct the error.
Again I ask your help.