you can assign a style sheet by the following
e.Row.Attributes("onMouseOver") = "this.className='RSHover'"
If e.Row.RowIndex Mod 2 = 0 Then
e.Row.Attributes("onMouseOut") = "this.className='GridRowStyle'"
Else
e.Row.Attributes("onMouseOut") = "this.className='GridAlternatingRowStyle'"
End If