Get Gridview datakeys on selectedIndexchanging method

See more:

VB

Gridview

Hello please i need help on how to get a gridview datakey value of a selected row that is binded manually from a linq to entity query. This is my query i used to bind the gridview

Dim searchClass = From cla In DemoSchool.RealClasses.OrderBy(Function(D) D.ClassCode).ThenBy(Function(P) P.ClassArm) _
                         Where cla.Session = drpSessionGrid.SelectedItem.Text
                            Select New With {Key .ClassSN = cla.ClassSN,
                                            Key .Class = cla.ClassCode,
                                            Key .ClassArm = cla.ClassArm}


       grdShowClassBySession.DataSource = searchClass
       grdShowClassBySession.DataBind()

The query works fine and the data is displayed on the gridview as expected, The problem is that i want to be able to retrieve the datakey of a selected row in the gridview selectedindexchanging method but i can't since the gridview is not bounded by a datasourceID like an entitydataSource control. I found a custom control from this url on codeproject
Simple GridView Radio Button Row Selector[^] .The control is able to fake the gridview selected row link button by using a radiobutton.But when i use it to get the datakey value of a selectedRow it gives an error saying Object not set to the instance of an object use the New Keyword

Private Sub grdShowClassBySession_SelectedIndexChanging(sender As Object, e As System.Web.UI.WebControls.GridViewSelectEventArgs) Handles grdShowClassBySession.SelectedIndexChanging
       Dim classS As String = grdShowClassBySession.DataKeys(grdShowClassBySession.SelectedIndex).Value.ToString




   End Sub

I have been cracking my head since and i have also passed by bedtime (hope i don't sleep in the office tomorrow) because of this problem.Any help is highly appreciated. If i can be pointed to a more workable solution to this problem i will be very grateful.Thanks as always