WPF DataGrid: CommandBinding to a double click instead of using Events

No need for attached behaviors or custom DataGrid subclasses here.

In your DataGrid, bind ItemsSource to an ICollectionView. The trick here is to set IsSynchronizedWithCurrentItem="True" which means the selected row will be the current item.

The second part of the trick is to bind CommandParameter to the current item with the forward slash syntax.

When a row is double clicked, the command will be executed with the clicked row as argument.

<DataGrid
    ItemsSource="{Binding CollectionView}"
    IsSynchronizedWithCurrentItem="True">
    <DataGrid.InputBindings>
        <MouseBinding
            MouseAction="LeftDoubleClick"
            Command="{Binding DoubleClickCommand}"
            CommandParameter="{Binding CollectionView/}"/>
    </DataGrid.InputBindings>
</DataGrid>

This is how a (simplified) version of the view model would look:

class MyViewModel
{
    public ICollectionView CollectionView { get; set; }

    public ICommand DoubleClickCommand { get; set; }
}