SqlCommand cmd = new SqlCommand(testoquery, cn);

            cmd.Parameters.Add("@anno", SqlDbType.DateTime);
            cmd.Parameters.Add("@announo", SqlDbType.DateTime);
            cmd.Parameters.Add("@annodue", SqlDbType.DateTime);

            cmd.Parameters["@anno"].Value = DateTime.Now.ToShortDateString();
            cmd.Parameters["@announo"].Value = DateTime.Now.AddYears(-1).ToShortDateString();
            cmd.Parameters["@annodue"].Value = DateTime.Now.AddYears(-2).ToShortDateString();