SqlConnection conn = new SqlConnection("data source=.\SQLEXPRESS; initial catalog=forum; user id=sa; password=moomin63549;";

string sql = "insert into users(email, userpass, accesslevel) values(@mail, @pass, @lvl)";

List<SqlParameter> args = new List<SqlParameter>();
args.Add(new SqlParameter("@mail", txtEmail.Text);
args.Add(new SqlParameter("@pass", HashIt(txtPassword.Text)); // HashIt function returns a hashed string for the password value
args.Add(new SqlParameter("@lvl", ddlAccessLevel.SelectedItem.Value);

SqlCommand cmd = new SqlCommand(sql, conn);
cmd.Parameters.AddRange(args.ToArray());