How can I disable editing cells in a WPF Datagrid?

The DataGrid has an XAML property IsReadOnly that you can set to true:

<my:DataGrid
    IsReadOnly="True"
/>

The WPF DataGrid has an IsReadOnly property that you can set to True to ensure that users cannot edit your DataGrid's cells.

You can also set this value for individual columns in your DataGrid as needed.