几个C#数据库封装类

由于SqlDataReader需要一个长效连接的原因，把它从CMySqlConnection中独立了出来，感觉有些松散，另外也有点重复封装的味道，不过实际使用中方便了许多，不用经常打开关闭数据库，省了不少。

 

class CMySqlConnection //SqlConnection封装类 { private SqlConnection m_objConn; //基于连接字符串构建对象 public CMySqlConnection(string strConnString) { m_objConn = new SqlConnection(strConnString); } //打开数据库连接 private void Open() { Close(); m_objConn.Open(); } //关闭数据库连接 private void Close() { if(m_objConn.State == ConnectionState.Open) m_objConn.Close(); } //执行Sql语句(不返回记录集的) private int ExecSql(string strSql) { int nRet = 0; try { this.Open(); SqlCommand objSqlCommand = new SqlCommand(strSql, m_objConn); nRet = objSqlCommand.ExecuteNonQuery(); this.Close(); } catch (Exception objException) { MessageBox.Show("执行SQL语句时出错，出错信息为：" + objException.ToString(), "错误"); } return nRet; //返回SQL语句执行后所影响的行数 } //执行一个查询操作 public DataSet doSelect(string strSql,string strTableName) { DataSet objDataSet = null; SqlDataAdapter objDataAdapter = null; try { this.Open(); objDataSet = new DataSet(); objDataAdapter = new SqlDataAdapter(strSql, m_objConn); objDataAdapter.Fill(objDataSet, strTableName); this.Close(); } catch (Exception objException) { MessageBox.Show("执行SQL语句时出错，出错信息为：" + objException.ToString(), "错误"); } return objDataSet; } //执行一个插入操作 public int doInsert(string strSql) { return ExecSql(strSql); } //执行一个更新操作 public int doUpdate(string strSql) { return ExecSql(strSql); } //执行一个删除操作 public int doDelete(string strSql) { return ExecSql(strSql); } }

 

class CMySqlDataReader //SqlDataReader封装类 { private bool m_bIsSelfConn; //是否新建数据库连接标志 private SqlConnection m_objConn; //数据库连接对象 private SqlDataReader m_objSqlDataReader; //阅读器对象 //新建一个数据库连接构建对象 public CMySqlDataReader(string strConnString) { m_objConn = new SqlConnection(strConnString); try { m_objConn.Open(); m_bIsSelfConn = true; } catch (Exception objException) { MessageBox.Show("打开数据库连接时出错，出错信息为：" + objException.ToString(), "错误"); } } //基于一个现存的数据库连接对象(必须已打开)构建对象 public CMySqlDataReader(SqlConnection objConn) { if (objConn.State == ConnectionState.Open) { m_objConn = objConn; m_bIsSelfConn = false; } else { throw new Exception("数据库连接未打开！"); //如果连接未打开则抛出异常 } } //打开并获得一个阅读器 public SqlDataReader Open(string strSql) { SqlCommand objSqlCommand = null; m_objSqlDataReader = null; try { objSqlCommand = new SqlCommand(strSql, m_objConn); m_objSqlDataReader = objSqlCommand.ExecuteReader(); } catch (Exception objException) { MessageBox.Show("创建一个SqlDataReader时出错，出错信息为：" + objException.ToString(), "错误"); } return m_objSqlDataReader; } //关闭一个阅读器 public void Close() { m_objSqlDataReader.Close(); if (m_bIsSelfConn) //如果数据库连接为新建的，则关闭它 { if (m_objConn.State == ConnectionState.Open) m_objConn.Close(); } } }