Master-Detail in wpf

See more:

C#

WPF

DataGrid

data-binding

Hello I am trying to create a details DataGrid for a Master ID
However when I enter a new ID and try to edit the details DataGrid the new details record disappears from the DataGrid but is stored in the DataTable and I can see it when I reload the project.

XAML
I am using CollectionViewSource and they display the Master Detail scenario just fine but when it comes to updating.
Here I create a new record where the User inputs new ID and new Details for the ID
This works fine.

button click
    {
    CollectionViewSource vs = (CollectionViewSource)FindResource("CVSVouchers);
                    ObjectDataProvider odp = (ObjectDataProvider)FindResource("Vouchers");
                    DataView dv = (DataView)odp.Data;
                    dv.AddNew();           
                    vs.View.MoveCurrentToLast();
    
    }

and I handle the Datagrids Row EditEnding

Datagrid RowEditEnding
{
            
                DataGridRow gridrow = e.Row;
                DataRowView drv = gridrow.Item as DataRowView;
                DataSet.ExpensesRow ExpRow = drv.Row as DataSet.ExpensesRow;
                actExpRow.VoucherSN = float.Parse(this.txtID.Text);

}

then the record disappears from the DataGrid but is saved in the DateTable.