使用DbHelper进行数据库操作的通用类实现

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

    public class DbHelper
    {
        private static string dbProviderName = ConfigurationManager.AppSettings["DbHelperProvider"];
        private static string dbConnectionString = ConfigurationManager.AppSettings["DbHelperConnectionString"];

        private DbConnection connection;
        public DbHelper()
        {
            this.connection = CreateConnection(DbHelper.dbConnectionString);
        }
        public DbHelper(string connectionString)
        {
            this.connection = CreateConnection(connectionString);
        }
        public static DbConnection CreateConnection()
        {
            DbProviderFactory dbfactory = DbProviderFactories.GetFactory(DbHelper.dbProviderName);
            DbConnection dbconn = dbfactory.CreateConnection();
            dbconn.ConnectionString = DbHelper.dbConnectionString;
            return dbconn;
        }
        public static DbConnection CreateConnection(string connectionString)
        {
            DbProviderFactory dbfactory = DbProviderFactories.GetFactory(DbHelper.dbProviderName);
            DbConnection dbconn = dbfactory.CreateConnection();

            dbconn.ConnectionString = connectionString;
            return dbconn;
        }

        public DbCommand GetStoredProcCommond(string storedProcedure)
        {
            DbCommand dbCommand = connection.CreateCommand();
            dbCommand.CommandText = storedProcedure;
            dbCommand.CommandType = CommandType.StoredProcedure;
            return dbCommand;
        }
        public DbCommand GetSqlStringCommond(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();