I'm working on a class using a tutorial and I'm wondering about something I'm seeing.

<vbcode>
<System.ComponentModel.DataObject()> _
Public Class ProductsBLL

Private _productsAdapter As ProductsTableAdapter = Nothing
Protected ReadOnly Property Adapter() As ProductsTableAdapter
Get
If _productsAdapter Is Nothing Then
_productsAdapter = New ProductsTableAdapter()
End If

Return _productsAdapter
End Get
End Property

End Class</vbcode>

Why all the underscores (_) ??
In the _productsAdapter declaration, why the underscore?

I'm confused.

Thanks!