If you are using a derived DataGrid, then you can check the Visible property on the protected VertScrollBar property of DataGrid. So, you could check Me.VertScrollBar.Visible from within your derived DataGrid.

To check it without access to the protected scrollbar properties is a little more work, but possible. One technique is to loop through the Controls property of the DataGrid looking for the scrollbar, and then checking its visible property at that time. Here's a method that illustrates the technique.

[C#]

private bool IsScrollBarVisible( Control control )
{
  foreach( Control c in control.Controls )
    if ( c.GetType().Equals( typeof( VScrollBar ) ) )
      return c.Visible;

  return false;
}

[Visual Basic]

Private Function IsScrollBarVisible(ByVal control As Control) As Boolean
  For Each c As Control In control.Controls
    If c.GetType() Is GetType(VScrollBar) Then
      Return c.Visible
    End If
  Next
  Return False
End Function

Contributed from George Shepherd's Windows Forms FAQ