以下是代码,很简单的,没有做任何多余的封装,只是改变了ADO.NET的编码步骤,方便了具体开发数据库操作代码的程序员.

    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;          }            #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            #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                    #region 执行事务          public DataSet ExecuteDataSet(DbCommand cmd,Trans 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, Trans 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, Trans 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, Trans t)          {              cmd.Connection.Close();              cmd.Connection = t.DbConnection;              cmd.Transaction = t.DbTrans;                int ret = cmd.ExecuteNonQuery();                          return ret;          }            public object ExecuteScalar(DbCommand cmd, Trans t)          {              cmd.Connection.Close();              cmd.Connection = t.DbConnection;              cmd.Transaction = t.DbTrans;                object ret = cmd.ExecuteScalar();                          return ret;          }          #endregion      }        public class Trans : IDisposable      {          private DbConnection conn;          private DbTransaction dbTrans;          public DbConnection DbConnection          {              get { return this.conn; }          }          public DbTransaction DbTrans          {              get { return this.dbTrans; }          }            public Trans()          {              conn = DbHelper.CreateConnection();              conn.Open();              dbTrans = conn.BeginTransaction();          }          public Trans(string connectionString)          {              conn = DbHelper.CreateConnection(connectionString);              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();              }          }      }

那么如何使用它呢?下面我给出一些基本的使用示例,基本能满足你大部分的数据库操作需要了.

1)直接执行sql语句

        DbHelper db = new DbHelper();          DbCommand cmd = db.GetSqlStringCommond("insert t1 (id)values('haha')");          db.ExecuteNonQuery(cmd);

2)执行存储过程

        DbHelper db = new DbHelper();          DbCommand cmd = db.GetStoredProcCommond("t1_insert");          db.AddInParameter(cmd, "@id", DbType.String, "heihei");          db.ExecuteNonQuery(cmd);

3)返回DataSet

        DbHelper db = new DbHelper();          DbCommand cmd = db.GetSqlStringCommond("select * from t1");          DataSet ds = db.ExecuteDataSet(cmd);

4)返回DataTable

        DbHelper db = new DbHelper();          DbCommand cmd = db.GetSqlStringCommond("t1_findall");          DataTable dt = db.ExecuteDataTable(cmd);

5)输入参数/输出参数/返回值的使用(比较重要哦)

        DbHelper db = new DbHelper();          DbCommand cmd = db.GetStoredProcCommond("t2_insert");          db.AddInParameter(cmd, "@timeticks", DbType.Int64, DateTime.Now.Ticks);          db.AddOutParameter(cmd, "@outString", DbType.String, 20);          db.AddReturnParameter(cmd, "@returnValue", DbType.Int32);            db.ExecuteNonQuery(cmd);            string s = db.GetParameter(cmd, "@outString").Value as string;//out parameter          int r = Convert.ToInt32(db.GetParameter(cmd, "@returnValue").Value);//return value

6)DataReader使用

        DbHelper db = new DbHelper();          DbCommand cmd = db.GetStoredProcCommond("t2_insert");          db.AddInParameter(cmd, "@timeticks", DbType.Int64, DateTime.Now.Ticks);          db.AddOutParameter(cmd, "@outString", DbType.String, 20);          db.AddReturnParameter(cmd, "@returnValue", DbType.Int32);            using (DbDataReader reader = db.ExecuteReader(cmd))          {              dt.Load(reader);          }                  string s = db.GetParameter(cmd, "@outString").Value as string;//out parameter          int r = Convert.ToInt32(db.GetParameter(cmd, "@returnValue").Value);//return value

7)事务的使用.(项目中需要将基本的数据库操作组合成一个完整的业务流时,代码级的事务是必不可少的哦)

    pubic void DoBusiness()      {          using (Trans t = new Trans())          {              try              {                  D1(t);                  throw new Exception();//如果有异常,会回滚滴                  D2(t);                  t.Commit();              }              catch              {                  t.RollBack();              }          }      }      public void D1(Trans t)      {          DbHelper db = new DbHelper();          DbCommand cmd = db.GetStoredProcCommond("t2_insert");          db.AddInParameter(cmd, "@timeticks", DbType.Int64, DateTime.Now.Ticks);          db.AddOutParameter(cmd, "@outString", DbType.String, 20);          db.AddReturnParameter(cmd, "@returnValue", DbType.Int32);            if (t == null) db.ExecuteNonQuery(cmd);          else db.ExecuteNonQuery(cmd,t);            string s = db.GetParameter(cmd, "@outString").Value as string;//out parameter          int r = Convert.ToInt32(db.GetParameter(cmd, "@returnValue").Value);//return value      }      public void D2(Trans t)      {          DbHelper db = new DbHelper();          DbCommand cmd = db.GetSqlStringCommond("insert t1 (id)values('..')");                  if (t == null) db.ExecuteNonQuery(cmd);          else db.ExecuteNonQuery(cmd, t);      }

以上我们好像没有指定数据库连接字符串,大家如果看下DbHelper的代码,就知道要使用它必须在config中配置两个参数,如下:

    <appSettings>          <add key="DbHelperProvider" value="System.Data.SqlClient"/>          <add key="DbHelperConnectionString" value="Data Source=(local);Initial Catalog=DbHelperTest;Persist Security Info=True;User ID=sa;Password=sa"/>      </appSettings>

其实,DbHelper需要的仅仅是两个字符串,你可以自己修改,作成加密什么的...

好了,就这样,DbHelper的代码是非常简单和透明的,只是在ado.net上做了一点小包装,改变了一下使用它的程序员的编码方式,去除掉一些比较"物理级"的编程概念,如connection的open和close之类的,使程序员更专注于业务逻辑代码的编写,少死掉点脑细胞,另外,统一了数据操作层的数据操作代码的风格和格式,维护起来很方便的撒~~~