[WPF] DatePicker and StringFormat

Hi,

in my grid I'm using a DatePicker (for show and edit).

When I edit the cells with Datepicker the format of date is "MM/dd/yyyy", how can I convert it in "dd/MM/yyyy"?

Why?

<DataGridTemplateColumn Header="{StaticResource datagridDatetime}"><DataGridTemplateColumn.CellTemplate><DataTemplate><TextBlock Text="{Binding DateTime, Mode=OneWay, StringFormat='dd/MM/yyyy'}"></TextBlock></DataTemplate></DataGridTemplateColumn.CellTemplate><DataGridTemplateColumn.CellEditingTemplate><DataTemplate><DatePicker SelectedDate="{Binding DateTime, StringFormat='dd/MM/yyyy'}"   /></DataTemplate></DataGridTemplateColumn.CellEditingTemplate></DataGridTemplateColumn>

Thanks.