This repository contains an example using a XAML behavior to synchronize the selection of rows in a DataGrid with a ViewModel in WPF.
It defines a DataGridExtensions.SynchronizeSelection attached property that can be set on a DataGrid:
<DataGrid ItemsSource="{Binding Items}"
b:DataGridExtensions.SynchronizeSelection="{Binding SelectedItem}"/>(see MainView.axaml)
When set, the attached property will synchronize the selection of rows in the DataGrid with each bound row model. The behavior assumes that the model implements IsSelectable and hence has a boolean IsSelected property.