After page postback, DropDownList item attributes "color" cleared ?

DropDownList1.SelectedItem.Attributes.Add("style", "Color:GREEN")
This is set when a person clicks a button, "resubmit order"... then the selected item is turned green so they kNow they've already fixed that order item.
Now if I select a different item, the page posts back to grab new @R_441_4045@ion for another order...., but the prevIoUsly set dropdownlist item, is no longer green.
I'm not refilling the dropdown, if the postback=true, so I have no idea why the viewstate is not keeping the attributes of the dropdown list items.
How can I preserve the color of dropdownlist items, after a postback ?

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Try this:
Protected Sub Page_PreRender(ByVal sender As Object, ByVal e As EventArgs)
    For Each index As Integer In Me.SelectedItems
        DropDownList1.Items(index).Attributes.Add("style", "Color:GREEN;background:red")
    Next
End Sub

Protected Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs)
    'DropDownList1.SelectedItem.Attributes.Add("style", "Color:GREEN");
    Dim selecteditems As List(Of Integer) = Me.SelectedItems
    selecteditems.Add(DropDownList1.Selectedindex)
    Me.SelectedItems = selecteditems
End Sub

Private _SelectedItems As List(Of Integer)
Public Property SelectedItems() As List(Of Integer)
    Get
        If ViewState("SelectedItems") IsNot nothing Then
            _SelectedItems = DirectCast(ViewState("SelectedItems"), List(Of Integer))
        Else
            _SelectedItems = New List(Of Integer)()
        End If
        Return _SelectedItems
    End Get
    Set(ByVal value As List(Of Integer))
        ViewState("SelectedItems") = value
    End Set
End Property

 

http://forums.asp.net/p/1159612/1913450.aspx

http://www.experts-exchange.com/Programming/Languages/.NET/ASP.NET/Q_25339597.html