protected void Page_Load(object sender, EventArgs e)
    {
        
        string connectionString = ConfigurationManager.ConnectionStrings["provaConnectionString4"].ConnectionString;
        SqlConnection conn = new SqlConnection(connectionString);
        SqlCommand comm = conn.CreateCommand();
        comm.CommandText = "Select tipologia, id, immagine, attacco from prodotti where inserto = @inserto";
        SqlParameter par = comm.CreateParameter();
        par.ParameterName = "@inserto";
        par.Value = Request.QueryString["inserto"]; // stringa, devi convertirlo se ti serve numero
        par.DbType = System.Data.DbType.String; //oppure il tuo tipo, ma occhio alla conversione da stringa
        comm.Parameters.Add(par);

        DataSet ds = new DataSet();
        SqlDataAdapter da = new SqlDataAdapter(comm.CommandText, conn);
        conn.Open();
        da.Fill(ds, "prova");
        conn.Close();
        GridView1.DataSource = ds.Tables[0];
        GridView1.DataBind();

    }