Transfer selected rows form gridview1 to gridview2 using LINQ to SQL

.NET
1

I would like to transfer the selected rows from gridview1 to gridview2, but I am able to do only the primary key column into the
second grid.
How to modify the code to have all columns displayed/ is there a better way to do it?
The code:

protected void Button1_Click(object sender, EventArgs e)
{
DataClassesDataContext context = new DataClassesDataContext();

    var f = from z in context.Availabilities
            join p in context.Items
            on z.ItemID equals p.ItemID
            join x in context.CDs
            on p.ItemID equals x.itemID
            join t in context.Artists
            on p.ItemID equals t.itemID
            group z by new { z.ItemID, t.artistName, p.Price, x.albumName, x.recordingStudio, x.CdID } into g
            select new { itemID = g.Key.ItemID, albumName = g.Key.albumName, Artists = g.Key.artistName, recordingStudio = g.Key.recordingStudio, Price = g.Key.Price, totalQty = g.Sum(z => z.Quantity) };

    GridView1.DataSource = f;

GridView1.DataBind();
}
protected void Button4_Click1(object sender, EventArgs e)
{
DataClassesDataContext context = new DataClassesDataContext();

    var selectedProducts = GridView1.Rows.Cast<GridViewRow>()
      .Where(row => ((CheckBox)row.FindControl("SelectedProducts")).Checked)
      .Select(row => GridView1.DataKeys[row.RowIndex].Value.ToString()).ToList();
    
    if (Session["Cart"] == null)
    {
        Session["Cart"] = selectedProducts;
    }
    else
    {
        var cart = (List<string>)Session["Cart"];
        foreach (var product in selectedProducts)
            cart.Add(product);
        Session["Cart"] = cart;
    }
    foreach (GridViewRow row in GridView1.Rows)
    {
        CheckBox cb = (CheckBox)row.FindControl("SelectedProducts");
        if (cb.Checked)
            cb.Checked = false;
    }


    GridView2.DataSource = selectedProducts;
    GridView2.DataBind();

}