今意外看见一贴子谈oledbhelper，突然想起自已一直用的由sqlhelper类转成的oledbhelper，在此分享，自己用了二年了，还没发现异常， 代码如下： using system; using system.data; using system.data.oledb; using system.configuration; using system.colle
    今意外看见一贴子谈oledbhelper，突然想起自已一直用的由sqlhelper类转成的oledbhelper，在此分享，自己用了二年了，还没发现异常， 代码如下：
using system;using system.data;using system.data.oledb;using system.configuration;using system.collections;using system.data.sql;using system.text;namespace lihui.common{    ///     /// summary description for oledbhelper    ///     public class oledbhelper    {        //database connection strings        public static readonly string conn_string = configurationmanager.appsettings[oledbconnectionstring];        public static readonly string conn_string1 = configurationmanager.appsettings[oledbconnectionstring1];        // hashtable to store cached parameters        private static hashtable parmcache = hashtable.synchronized(new hashtable());        #region =executenonquery=        public static int executenonquery(string connstring, commandtype cmdtype, string cmdtext)        {            return executenonquery(connstring, cmdtype, cmdtext, null);        }        public static int executenonquery(oledbconnection conn, commandtype cmdtype, string cmdtext)        {            return executenonquery(conn, cmdtype, cmdtext, null);        }        public static int executenonquery(oledbtransaction trans, commandtype cmdtype, string cmdtext)        {            return executenonquery(trans, cmdtype, cmdtext, null);        }        public static int executenonquery(string connstring, commandtype cmdtype, string cmdtext, params oledbparameter[] cmdparms)        {            oledbcommand cmd = new oledbcommand();            using (oledbconnection conn = new oledbconnection(connstring))            {                preparecommand(cmd, conn, null, cmdtype, cmdtext, cmdparms);                int val = cmd.executenonquery();                //清除cmd的参数                cmd.parameters.clear();                if (conn.state == connectionstate.open)                {                    conn.close();                }                return val;            }        }        public static int executenonquery(oledbconnection conn, commandtype cmdtype, string cmdtext, params oledbparameter[] cmdparms)        {            oledbcommand cmd = new oledbcommand();            preparecommand(cmd, conn, null, cmdtype, cmdtext, cmdparms);            int val = cmd.executenonquery();            cmd.parameters.clear();            if (conn.state == connectionstate.open)            {                conn.close();            }            return val;        }        public static int executenonquery(oledbtransaction trans, commandtype cmdtype, string cmdtext, params oledbparameter[] cmdparms)        {            oledbcommand cmd = new oledbcommand();            preparecommand(cmd, trans.connection, trans, cmdtype, cmdtext, cmdparms);            int val = cmd.executenonquery();            cmd.parameters.clear();            if (cmd.connection.state == connectionstate.open)            {                cmd.connection.close();            }            return val;        }        #endregion        #region =executereader=        public static oledbdatareader executereader(string connectionstring, commandtype commandtype, string commandtext)        {            //pass through the call providing null for the set of oledbparameters            return executereader(connectionstring, commandtype, commandtext, (oledbparameter[])null);        }        public static oledbdatareader executereader(string connstring, commandtype cmdtype, string cmdtext, params oledbparameter[] cmdparms)        {            oledbcommand cmd = new oledbcommand();            oledbconnection conn = new oledbconnection(connstring);            try            {                preparecommand(cmd, conn, null, cmdtype, cmdtext, cmdparms);                oledbdatareader rdr = cmd.executereader(commandbehavior.closeconnection);                cmd.parameters.clear();                if (conn.state == connectionstate.open)                {                    conn.close();                }                return rdr;            }            catch            {                conn.close();                throw;            }        }        #endregion        #region =executedataset=        public static dataset executedataset(string connectionstring, commandtype commandtype, string commandtext)        {            return executedataset(connectionstring, commandtype, commandtext, (oledbparameter[])null);        }        public static dataset executedataset(string connectionstring, commandtype commandtype, string commandtext, params oledbparameter[] commandparameters)        {            using (oledbconnection cn = new oledbconnection(connectionstring))            {                cn.open();                //调用重载方法                return executedataset(cn, commandtype, commandtext, commandparameters);            }        }        public static dataset executedataset(oledbconnection connection, commandtype commandtype, string commandtext)        {            return executedataset(connection, commandtype, commandtext, (oledbparameter[])null);        }        public static dataset executedataset(oledbconnection connection, commandtype commandtype, string commandtext, params oledbparameter[] commandparameters)        {            //创建一个oledbcommand对象，并对其进行初始化            oledbcommand cmd = new oledbcommand();            preparecommand(cmd, connection, (oledbtransaction)null, commandtype, commandtext, commandparameters);            //创建oledbdataadapter对象以及dataset            oledbdataadapter da = new oledbdataadapter(cmd);            dataset ds = new dataset();            //填充ds            da.fill(ds);            // 清除cmd的参数集合               cmd.parameters.clear();            if (cmd.connection.state == connectionstate.open)            {                cmd.connection.close();            }            //返回ds            return ds;        }        #endregion        #region =executedatatable=        public static datatable executedatatable(string connectionstring, commandtype commandtype, string commandtext)        {            return executedatatable(connectionstring, commandtype, commandtext, (oledbparameter[])null);        }        public static datatable executedatatable(string connectionstring, commandtype commandtype, string commandtext, params oledbparameter[] commandparameters)        {            using (oledbconnection cn = new oledbconnection(connectionstring))            {                cn.open();                //调用重载方法                return executedatatable(cn, commandtype, commandtext, commandparameters);            }        }        public static datatable executedatatable(oledbconnection connection, commandtype commandtype, string commandtext)        {            return executedatatable(connection, commandtype, commandtext, (oledbparameter[])null);        }        public static datatable executedatatable(oledbconnection connection, commandtype commandtype, string commandtext, params oledbparameter[] commandparameters)        {            //创建一个oledbcommand对象，并对其进行初始化            oledbcommand cmd = new oledbcommand();            preparecommand(cmd, connection, (oledbtransaction)null, commandtype, commandtext, commandparameters);            //创建oledbdataadapter对象以及dataset            oledbdataadapter da = new oledbdataadapter(cmd);            dataset ds = new dataset();            //填充ds            da.fill(ds);            // 清除cmd的参数集合               cmd.parameters.clear();            if (cmd.connection.state == connectionstate.open)            {                cmd.connection.close();            }            //返回ds            return ds.tables[0];        }        #endregion        #region =executescalar=        public static object executescalar(string connstring, commandtype cmdtype, string cmdtext)        {            return executescalar(connstring, cmdtype, cmdtext, null);        }        public static object executescalar(string connstring, commandtype cmdtype, string cmdtext, params oledbparameter[] cmdparms)        {            oledbcommand cmd = new oledbcommand();            using (oledbconnection conn = new oledbconnection(connstring))            {                preparecommand(cmd, conn, null, cmdtype, cmdtext, cmdparms);                object val = cmd.executescalar();                cmd.parameters.clear();                if (conn.state == connectionstate.open)                {                    conn.close();                }                return val;            }        }        public static object executescalar(oledbconnection conn, commandtype cmdtype, string cmdtext)        {            return executescalar(conn, cmdtype, cmdtext, null);        }        public static object executescalar(oledbconnection conn, commandtype cmdtype, string cmdtext, params oledbparameter[] cmdparms)        {            oledbcommand cmd = new oledbcommand();            preparecommand(cmd, conn, null, cmdtype, cmdtext, cmdparms);            object val = cmd.executescalar();            cmd.parameters.clear();            if (conn.state == connectionstate.open)            {                conn.close();            }            return val;        }        #endregion        public static void cacheparameters(string cachekey, params oledbparameter[] cmdparms)        {            parmcache[cachekey] = cmdparms;        }        public static oledbparameter[] getcachedparameters(string cachekey)        {            oledbparameter[] cachedparms = (oledbparameter[])parmcache[cachekey];            if (cachedparms == null)                return null;            oledbparameter[] clonedparms = new oledbparameter[cachedparms.length];            for (int i = 0, j = cachedparms.length; i                 clonedparms[i] = (oledbparameter)((icloneable)cachedparms[i]).clone();            return clonedparms;        }        public static void preparecommand(oledbcommand cmd, oledbconnection conn, oledbtransaction trans, commandtype cmdtype, string cmdtext, oledbparameter[] cmdparms)        {            //判断连接的状态。如果是关闭状态，则打开            if (conn.state != connectionstate.open)                conn.open();            //cmd属性赋值            cmd.connection = conn;            cmd.commandtext = cmdtext;            //是否需要用到事务处理            if (trans != null)                cmd.transaction = trans;            cmd.commandtype = cmdtype;            //添加cmd需要的存储过程参数            if (cmdparms != null)            {                foreach (oledbparameter parm in cmdparms)                    cmd.parameters.add(parm);            }        }    }}    使用方法跟sqlhelper类相似。