You will have to manually create your columns instead of AutoGenerating them. Then you can bind your manually created columns to the specific properties you want to display. Something like this:-
<DataGrid AutoGenerateColumns="False">
<DataGrid.Columns>
<DataGridTextColumn Binding="{Binding Path=Name}" Header="Name"/>
<DataGridTextColumn Binding="{Binding Path=Surname}" Header="Surname"/>
<DataGridTextColumn Binding="{Binding Path=Age}" Header="Age"/>
<DataGridTextColumn Binding="{Binding Path=EmployeeNo}" Header="Employee Number"/>
</DataGrid.Columns>
</DataGrid>