在这种情况下，asp.net中的静态方法是一个坏主意吗？

Question

i have a DAL CLASS which is like Below

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.SqlClient;

namespace SomeNameSpace
{
    public class DAL
    {
        public  string _ConnectionString = System.Configuration.ConfigurationManager.ConnectionStrings["xClassConnectionString"].ConnectionString;

        public static DataSet GetDataSet(string sql)
        {
            try
            {
                using (SqlConnection connection2 = new SqlConnection(Convert.ToString(System.Configuration.ConfigurationManager.ConnectionStrings["xClassConnectionString"].ConnectionString)))
                {
                    SqlCommand cmd = new SqlCommand(sql, connection2);
                    SqlDataAdapter adp = new SqlDataAdapter(cmd);
                    //   Connection.Close();
                    DataSet ds = new DataSet();
                    adp.Fill(ds);
                    return ds;
                }

            }
            catch (SqlException err)
            {
                // Replace the error with something less specific.
                // You could also log the error now.
                throw new ApplicationException("Data error. " + err.Message.ToString());
            }

        }

        public static DataSet GetDataSet(string sql, Dictionary<string, dynamic> dictionary)
        {
            try
            {
                using (SqlConnection connection2 = new SqlConnection(Convert.ToString(System.Configuration.ConfigurationManager.ConnectionStrings["xClassConnectionString"].ConnectionString)))
                {
                    SqlCommand cmd = new SqlCommand(sql, connection2);
                    cmd.CommandType = CommandType.Text;
                    //Dictionary<string, dynamic> dictionary = new Dictionary<string, dynamic>();
                    foreach (KeyValuePair<string, dynamic> pair in dictionary)
                    {
                        cmd.Parameters.AddWithValue(pair.Key, pair.Value);
                    }

                    SqlDataAdapter adp = new SqlDataAdapter(cmd);

                    DataSet ds = new DataSet();
                    adp.Fill(ds);

                    return ds;
                }

            }
            catch (SqlException err)
            {
                // Replace the error with something less specific.
                // You could also log the error now.
                throw new ApplicationException("Data error. " + err.Message.ToString());
            }

        }


        public static DataTable GetDataTable(string sql)
        {
            DataSet ds = GetDataSet(sql);

            if (ds.Tables.Count > 0)
                return ds.Tables[0];
            return null;
        }


        public static int ExecuteSQL(string sql)
        {
            try
            {
                using (SqlConnection connection2 = new SqlConnection(Convert.ToString(System.Configuration.ConfigurationManager.ConnectionStrings["xClassConnectionString"].ConnectionString)))
                {
                    string BegSql = "BEGIN TRY BEGIN TRANSACTION ";
                    string EndSql = " COMMIT TRANSACTION END TRY BEGIN CATCH  ROLLBACK TRANSACTION END CATCH";
                    string NewSql = BegSql + sql + EndSql;
                    sql = NewSql;
                    SqlCommand cmd = new SqlCommand(sql, connection2);
                    connection2.Open();
                    return cmd.ExecuteNonQuery();
                }

            }
            catch (System.Exception ex)
            {
                return -1;
            }

        }

    }
}

i also have a BAL class which holds all the function

using Newtonsoft.Json;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Data;
using System.IO;
using System.Net;
using System.Net.Mail;
using System.Web;
using System.Web.Script.Serialization;
using System.Web.UI;

namespace SomeNameSpace
{
    public class BAL
    {

        public static int getUserID(string user_name)
        {
            try
            {
                //string sql = "select user_id from CI_Users where user_name=@user_name";
                string sql = "select user_id from CI_Users where user_name=1";
                return Convert.ToInt32(DAL.GetDataTable(sql).Rows[0][0]);
            }
            catch (System.Exception ex)
            {
                throw new ApplicationException("Data error." + ex.Message.ToString());
            }
        }

    }
}

my question is

Is this a good/bad idea to write all functions in BAL as static ? i will call BAL to do all operations.

public static int getUserID(string user_name)

Answer 1

In my opinion, your current design is no problem. The moment you should start worrying when using static classes is when you want to keep variables alive.

Static variables in ASP.NET are kept over sessions. So when you save a user id in a static variable, that might cross different users' sessions.

Answer 2

There are 2 approaches in designing BALs 1.Stateless 2.Statefull

Makeing methods as a static member is one of Stateless designs for example you can't have a variable in your class to set in one method and use in another for every call (of course you acn have it static too but it's value is global and is not advised in web application)

Also if you want to have some cross cutting (such as logging, transaction, ...) codes you have to have non static members and classes.

By the way if you are developing a small application it is OK and if you are developing an enterprise application rethink about that