How can I highlight an entire DataGrid row when a single cell is clicked?

Question

I have a DataGrid defined as follows. When I click a cell in the DataGrid only the cell is highlighted. How can I change it so that when I click the cell the entire row is highlighted?

<DataGrid Name="fileGrid" AutoGenerateColumns="False" Height="150" Width="Auto" 
            Margin="10,10,0,0" 
            HorizontalAlignment="Left" VerticalAlignment="Top" SelectionChanged="fileGrid_SelectionChanged">
    <DataGrid.Columns>
        <DataGridTextColumn Header="Company Name" 
            x:Name="columnCompanyName" 
            Binding="{Binding Path=Customer.CompanyName}"
            IsReadOnly="True">                    
        </DataGridTextColumn>

        <DataGridTextColumn Header="Customer Surname" 
            x:Name="columnCustomerSurname" 
            Binding="{Binding Path=Customer.Surname}"
            IsReadOnly="True">
        </DataGridTextColumn>

        <DataGridTextColumn Header="Customer Address" 
            x:Name="columnAddressLine1" 
            Binding="{Binding Path=Customer.Address.Line1}"
            IsReadOnly="True">
        </DataGridTextColumn>

        <DataGridTextColumn Header="Customer City" 
            x:Name="columnCity" 
            Binding="{Binding Path=Customer.Address.City}"
            IsReadOnly="True">
        </DataGridTextColumn>

    </DataGrid.Columns>
</DataGrid>

Answer 1

Have you tried <DataGrid SelectionMode="Single" SelectionUnit="FullRow"> ?

But actually its the default behavior if i click a cell the entire row is highlighted

SelectionMode doc: https://msdn.microsoft.com/en-us/library/system.windows.controls.datagridselectionmode%28v=vs.110%29.aspx

SelectionUnit doc: https://msdn.microsoft.com/en-us/library/system.windows.controls.datagrid.selectionunit%28v=vs.110%29.aspx