Welcome to the WPF feedback portal. We’re happy you’re here! If you have feedback on how to improve the WPF, we’d love to hear it!>
Thanks for joining our community and helping improve Syncfusion products!
I have been told in Syncfusion Forum [179856] that "
there are no possibilities to achieve your requirement to “Show row numbers in the grid, using code behind", only through XAML.
mygrid.ShowRowNumbers = true;
The result of setting the property to true would be row numbers in the red boxed area here:

Hope I've explained the request clearly!
Pete