public class SqlHelper
    ...{
        ExecuteNonQuery的两个重载#region ExecuteNonQuery的两个重载
        public static int ExecuteNonQuery(string connStr, CommandType commandType, string commStr)
        ...{
            SqlConnection conn = new SqlConnection(connStr);
            SqlCommand comm = new SqlCommand(commStr, conn);
            comm.CommandType = commandType;

            conn.Open();
            int rowNum = comm.ExecuteNonQuery();
            comm.Dispose();
            conn.Close();

            return rowNum;
        }
        public static int ExecuteNonQuery(string connStr, CommandType commandType, string commStr, params SqlParameter[] commandParameters)
        ...{
            SqlConnection conn = new SqlConnection(connStr);
            SqlCommand comm = new SqlCommand(commStr, conn);
            comm.CommandType = commandType;

            for (int i = 0; i < commandParameters.Length; i++)
                comm.Parameters.Add(commandParameters[i]);

            conn.Open();
            int rowNum = comm.ExecuteNonQuery();
            comm.Dispose();
            conn.Close();

            return rowNum;
        }
        #endregion

        ExecuteScalar的两个重载#region ExecuteScalar的两个重载
        public static object ExecuteScalar(string connStr, CommandType commandType, string commStr)
        ...{
            SqlConnection conn = new SqlConnection(connStr);
            SqlCommand comm = new SqlCommand(commStr, conn);
            comm.CommandType = commandType;