If Session("dw") Is Nothing Then
Dim da As New OleDbDataAdapter("select * from log", cnn)
Dim ds As New DataSet()
da.Fill(ds, "employees")
Dim tb As DataTable = New DataTable()
tb = ds.Tables(0)
Dim dr As DataRow = tb.NewRow
tb.Rows.Add(dr)
Dim dw As DataView = New DataView(tb)
DataGrid1.DataSource = dw
DataGrid1.DataBind()
Session("dw") = dw
Else
Dim dw As DataView = New DataView()
dw = Session("dw")
Dim tb As DataTable = New DataTable()
tb = dw.Table
Dim dr As DataRow = tb.NewRow