Populate data table from database

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ASP.NET

SQL

WebForms

Hello world !
i'm developing a shopping cart in asp net.
Products : Db
Shopping Cart : Data Table
Order : Db (but order is not important now)

The connections string work fine, the only problem is this :
If i populate the data table with a insert into sql command, it work on db and i don't want it.
I want that the sql command write only on the data table and don't modify the Database.

What I have tried:

This is the code :

If Not Me.IsPostBack Then
           Dim constr As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
           Using con As New SqlConnection(constr)

               '

                   Using cmd As New SqlCommand("INSERT INTO Carrello (ID,Nome,PrezzoFloat, Quantità) SELECT Id,NomeProdotto, PrezzoProdotto, Quantità FROM aProdotti WHERE ID='2'")
                   cmd.Connection = con
                   Using sda As New SqlDataAdapter(cmd)
                       Dim dt As New DataTable()
                       sda.Fill(dt)
                       GridView1.DataSource = dt
                       GridView1.DataBind()
                   End Using
               End Using
           End Using


       End If