关于DbHelper的修改

我在前一篇文章中谈到了DbHelper这一个访问数据库的基础类，在用过之后发现有些地方还要修改一下才更加的完善。
首先应该把dbProviderName ，dbConnectionString 这两个static的字段放到默认的构造函数中，不然当你用自定义的连接字符串初始化类DbHelper db=new DbHelper("otherConnectionString")，而配置文件中又没有"connecionString"连接字符串时就会出错；当然这时改过后如果用默认的构造函数创建类也会出错，因为默认的是要有"connectionString"这一数据库连接字符串。后来又发觉既然配置文件中有connectionStrings这一配置节，为什么不把dbProviderName ，dbConnectionString 放在里面呢？
最后整理如下：
 

using System;
using System.Data;
using System.Data.Common;
using System.Configuration;

namespace namespace1
{
    public class DbHelper
    {
        private static string dbProviderName;

        private DbConnection connection;

        public DbHelper()
        {
            this.connection = CreateConnection();
        }

        public DbHelper(string cfgConnectionString)
        {
            this.connection = CreateConnection(cfgConnectionString);
        }

        public static DbConnection CreateConnection()
        {
            return CreateConnection("connectionString");
        }

        public static DbConnection CreateConnection(string cfgConnectionString)
        {            
            dbProviderName = ConfigurationManager.ConnectionStrings[cfgConnectionString].ProviderName;
            DbProviderFactory dbfactory = DbProviderFactories.GetFactory(dbProviderName);
            DbConnection dbconn = dbfactory.CreateConnection();
            dbconn.ConnectionString = ConfigurationManager.ConnectionStrings[cfgConnectionString].ConnectionString;
            return dbconn;
        }

        public DbCommand GetStoredProcCommand(string storedProcedure)
        {
            DbCommand dbCommand = connection.CreateCommand();
            dbCommand.CommandText = storedProcedure;
            dbCommand.CommandType = CommandType.StoredProcedure;
            return dbCommand;
        }
        public DbCommand GetSqlStringCommand(string sqlQuery)
        {
            DbCommand dbCommand = connection.CreateCommand();
            dbCommand.CommandText = sqlQuery;
            dbCommand.CommandType = CommandType.Text;
            return dbCommand;
        }

        增加参数#region 增加参数

        public void AddParameterCollection(DbCommand cmd, DbParameterCollection dbParameterCollection)
        {
            foreach (DbParameter dbParameter in dbParameterCollection)
            {
                cmd.Parameters.Add(dbParameter);
            }
        }

        public void AddOutParameter(DbCommand cmd, string parameterName, DbType dbType, int size)
        {
            DbParameter dbParameter = cmd.CreateParameter();
            dbParameter.DbType = dbType;
            dbParameter.ParameterName = parameterName;
            dbParameter.Size = size;
            dbParameter.Direction = ParameterDirection.Output;
            cmd.Parameters.Add(dbParameter);
        }

        public void AddInParameter(DbCommand cmd, string parameterName, DbType dbType, object value)
        {
            DbParameter dbParameter = cmd.CreateParameter();
            dbParameter.DbType = dbType;
            dbParameter.ParameterName = parameterName;
            dbParameter.Value = value;
            dbParameter.Direction = ParameterDirection.Input;
            cmd.Parameters.Add(dbParameter);
        }

        public void AddReturnParameter(DbCommand cmd, string parameterName, DbType dbType)
        {
            DbParameter dbParameter = cmd.CreateParameter();
            dbParameter.DbType = dbType;
            dbParameter.ParameterName = parameterName;
            dbParameter.Direction = ParameterDirection.ReturnValue;
            cmd.Parameters.Add(dbParameter);
        }

        public DbParameter GetParameter(DbCommand cmd, string parameterName)
        {
            return cmd.Parameters[parameterName];
        }

        #endregion

        执行#region 执行

        public DataSet ExecuteDataSet(DbCommand cmd)
        {
            DbProviderFactory dbfactory = DbProviderFactories.GetFactory(DbHelper.dbProviderName);
            DbDataAdapter dbDataAdapter = dbfactory.CreateDataAdapter();
            dbDataAdapter.SelectCommand = cmd;
            DataSet ds = new DataSet();
            dbDataAdapter.Fill(ds);
            return ds;
        }

        public DataTable ExecuteDataTable(DbCommand cmd)
        {
            DbProviderFactory dbfactory = DbProviderFactories.GetFactory(DbHelper.dbProviderName);
            DbDataAdapter dbDataAdapter = dbfactory.CreateDataAdapter();
            dbDataAdapter.SelectCommand = cmd;
            DataTable dataTable = new DataTable();
            dbDataAdapter.Fill(dataTable);
            return dataTable;
        }

        public DbDataReader ExecuteReader(DbCommand cmd)
        {
            cmd.Connection.Open();
            DbDataReader reader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
            return reader;
        }
        public int ExecuteNonQuery(DbCommand cmd)
        {
            cmd.Connection.Open();
            int ret = cmd.ExecuteNonQuery();
            cmd.Connection.Close();
            return ret;
        }

        public object ExecuteScalar(DbCommand cmd)
        {
            cmd.Connection.Open();
            object ret = cmd.ExecuteScalar();
            cmd.Connection.Close();
            return ret;
        }
        #endregion

        执行事务#region 执行事务

        public DataSet ExecuteDataSet(DbCommand cmd, Transaction t)
        {
            cmd.Connection = t.DbConnection;
            cmd.Transaction = t.DbTrans;
            DbProviderFactory dbfactory = DbProviderFactories.GetFactory(DbHelper.dbProviderName);
            DbDataAdapter dbDataAdapter = dbfactory.CreateDataAdapter();
            dbDataAdapter.SelectCommand = cmd;
            DataSet ds = new DataSet();
            dbDataAdapter.Fill(ds);
            return ds;
        }

        public DataTable ExecuteDataTable(DbCommand cmd, Transaction t)
        {
            cmd.Connection = t.DbConnection;
            cmd.Transaction = t.DbTrans;
            DbProviderFactory dbfactory = DbProviderFactories.GetFactory(DbHelper.dbProviderName);
            DbDataAdapter dbDataAdapter = dbfactory.CreateDataAdapter();
            dbDataAdapter.SelectCommand = cmd;
            DataTable dataTable = new DataTable();
            dbDataAdapter.Fill(dataTable);
            return dataTable;
        }

        public DbDataReader ExecuteReader(DbCommand cmd, Transaction t)
        {
            cmd.Connection.Close();
            cmd.Connection = t.DbConnection;
            cmd.Transaction = t.DbTrans;
            DbDataReader reader = cmd.ExecuteReader();
            DataTable dt = new DataTable();
            return reader;
        }
        public int ExecuteNonQuery(DbCommand cmd, Transaction t)
        {
            cmd.Connection.Close();
            cmd.Connection = t.DbConnection;
            cmd.Transaction = t.DbTrans;
            int ret = cmd.ExecuteNonQuery();
            return ret;
        }

        public object ExecuteScalar(DbCommand cmd, Transaction t)
        {
            cmd.Connection.Close();
            cmd.Connection = t.DbConnection;
            cmd.Transaction = t.DbTrans;
            object ret = cmd.ExecuteScalar();
            return ret;
        }
        #endregion
    }

    public class Transaction : IDisposable
    {
        private DbConnection conn;
        private DbTransaction dbTrans;

        public DbConnection DbConnection
        {
            get { return this.conn; }
        }

        public DbTransaction DbTrans
        {
            get { return this.dbTrans; }
        }

        public Transaction()
        {
            conn = DbHelper.CreateConnection();
            conn.Open();
            dbTrans = conn.BeginTransaction();
        }

        public Transaction(string cfgConnectionString)
        {
            conn = DbHelper.CreateConnection(cfgConnectionString);
            conn.Open();
            dbTrans = conn.BeginTransaction();
        }

        public void Commit()
        {
            dbTrans.Commit();
            this.Colse();
        }

        public void RollBack()
        {
            dbTrans.Rollback();
            this.Colse();
        }

        public void Dispose()
        {
            this.Colse();
        }

        public void Colse()
        {
            if (conn.State == System.Data.ConnectionState.Open)
            {
                conn.Close();
            }
        }
    }
}

还是放个文件上来吧：
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