How to get value from datagrid in WPF?

Question

SQL

Good afternoon.
How to actually get the value from the datagrid? I want to take the Id from the selected row and assign it to an int variable so that I can then pass it to the delete request. The base Id is also of type int. The task itself is to create something like a home library so that the datagrid displays the books.

private void ButtonDeleteBook_Click(object sender, RoutedEventArgs e)
        {
            HomeLibraryDatabaseEntities context = new HomeLibraryDatabaseEntities();
            try
            {
                int selectedId = ((Book)BookDG.SelectedItem).IdBook; 
                Book selectedBook = context.Book.Where(o => o.IdBook == selectedId ).Select(o => o).First();
                context.Book.Remove(selectedBook);
                context.SaveChanges();
                MessageBox.Show("Объект успешно удален");
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }

Book is a table in the DB and BookGD is a datagrid that displays books from the Book table. HomeLibraryDatabase - the actual name of the database.
When a row is selected and the "Delete" button is clicked, the Unable to cast object of type 'System.Data.DataRowView' to type 'HomeLibrary.Book' error occurs.

Answer 1

In general it is strange... How is the grid data source configured?
So?
those. interested in the type of the collection and the type of the elements of the collection

Answer 2

first,
int selected = ((Book)BookDG.SelectedItem)
context.Book.Remove(selectedBook);
context.SaveChanges();
MVVM and bindings will help you, just make a model, in it a property, for example, Selected, and write in the DataGrid, SelectedItem={Binding Selected, Mode=TwoWay}
and you can write
context.Book.Remove(Selected);
context.SaveChanges();
I recommend SimpleMVVM, simple, for small projects