Function to add record from ASP page to table is not working (VB.NET)

Unable to cast object of type 'System.Collections.Generic.List`1[System.String]' to type 'System.Array'.

Dim SlctdPhones As Array = CType(Session.Item("SlctdPhones"), Array)

Protected Sub Button1_Click(sender As Object, e As EventArgs) Handles CheckOut.Click

    Dim PNames As New List(Of String)()
     For Each index As Integer In ListBox1.GetSelectedIndices
         PNames.Add(ListBox1.Items(index).Text)
     Next
     Session("SlctdPhones") = PNames

     Response.Redirect("CheckOut.aspx?Name=" + Label2.Text + "&TPrice=" + Label1.Text)


 End Sub

Protected Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim SlctdPhones As Array = CType(Session.Item("SlctdPhones"), Array)
        Dim p As New Class1
        Dim y As Integer
        If (y = p.AddOrder(Label1.Text, SlctdPhones, CInt(Label2.Text))) = 1 Then

        End If
End Sub

Public Function AddOrder(ByVal Name As String, ByVal NArray() As String, ByVal TPrice As Integer) As Integer

       Dim connetionString As String = Nothing
       Dim connection As SqlConnection
       Dim command1, command2 As SqlCommand
       Dim adapter As New SqlDataAdapter()
       Dim ds As New DataSet()
       Dim sql1, sql2 As String
       connetionString = "Data Source=.;Initial Catalog=Shop;integrated security=true"
       connection = New SqlConnection(connetionString)
       connection.Open()

       'Dim table1 As DataTable = New DataTable("logins")
       'Dim table2 As DataTable = New DataTable("Orders")

       sql1 = "select * from Customer_Detail"
       command1 = New SqlCommand(sql1, connection)
       adapter.SelectCommand = command1
       adapter.Fill(ds, "logins")
       sql2 = "select * from CustomerOrders"
       command2 = New SqlCommand(sql2, connection)
       adapter.SelectCommand = command2
       adapter.Fill(ds, "Orders")
       adapter.Dispose()
       connection.Close()

       Dim rows() As DataRow = ds.Tables("logins").Select("Name = '" & Name & "'")
       Dim searchedValue As Integer
       If rows.Count > 0 Then
           searchedValue = CInt(rows(0).Item("LoginID"))
       End If
       Dim PhoneNames As String = ""
       For i As Integer = 0 To NArray.Length - 1
           PhoneNames = NArray(i).ToString + PhoneNames
       Next

       Dim dr As DataRow
       dr = ds.Tables("Orders").NewRow()
       dr("logIn") = searchedValue
       dr("PhoneNames") = PhoneNames
       dr("TotalPrice") = TPrice
       ds.Tables("Orders").Rows.Add(dr)

       adapter.SelectCommand = command2
       Dim ESCBuilder As SqlCommandBuilder = New SqlCommandBuilder(adapter)
       adapter.InsertCommand = ESCBuilder.GetInsertCommand()
       adapter.Update(ds, "Orders")

       Return 1
   End Function