代码 Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/-->using System;using System.Collections.Generic;using System.Text;using System.Data;using System.Data.SqlClient;using System.Collections;namespace SystemDAO{    /// <summary>    /// 数据库的通用访问代码 苏飞修改    ///     /// 此类为抽象类，    /// 不允许实例化，在应用时直接调用即可    /// </summary>    public abstract class SqlHelper    {        /// <summary>        /// 数据库连接字符串        /// </summary>        public static readonly string connectionString = System.Configuration.ConfigurationSettings.AppSettings["con"].ToString().Trim();        // Hashtable to store cached parameters        private static Hashtable parmCache = Hashtable.Synchronized(new Hashtable());        #region//ExecteNonQuery方法        /// <summary>        ///执行一个不需要返回值的SqlCommand命令，通过指定专用的连接字符串。        /// 使用参数数组形式提供参数列表         /// </summary>        /// <param name="connectionString">一个有效的数据库连接字符串</param>        /// <param name="cmdType">SqlCommand命令类型 (存储过程， T-SQL语句， 等等。)</param>        /// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>        /// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>        /// <returns>返回一个数值表示此SqlCommand命令执行后影响的行数</returns>        public static int ExecteNonQuery(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)        {            SqlCommand cmd = new SqlCommand();            using (SqlConnection conn = new SqlConnection(connectionString))            {                //通过PrePareCommand方法将参数逐个加入到SqlCommand的参数集合中                PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);                int val = cmd.ExecuteNonQuery();                //清空SqlCommand中的参数列表                cmd.Parameters.Clear();                return val;            }        }        /// <summary>        ///执行一个不需要返回值的SqlCommand命令，通过指定专用的连接字符串。        /// 使用参数数组形式提供参数列表         /// </summary>        /// <param name="cmdType">SqlCommand命令类型 (存储过程， T-SQL语句， 等等。)</param>        /// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>        /// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>        /// <returns>返回一个数值表示此SqlCommand命令执行后影响的行数</returns>        public static int ExecteNonQuery(CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)        {            return ExecteNonQuery(connectionString ,cmdType, cmdText, commandParameters);        }        /// <summary>        ///存储过程专用        /// </summary>        /// <param name="cmdText">存储过程的名字</param>        /// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>        /// <returns>返回一个数值表示此SqlCommand命令执行后影响的行数</returns>        public static int ExecteNonQueryProducts(string cmdText, params SqlParameter[] commandParameters)        {            return ExecteNonQuery(CommandType.StoredProcedure, cmdText, commandParameters);        }        /// <summary>        ///Sql语句专用        /// </summary>        /// <param name="cmdText">T_Sql语句</param>        /// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>        /// <returns>返回一个数值表示此SqlCommand命令执行后影响的行数</returns>        public static int ExecteNonQueryText(string cmdText, params SqlParameter[] commandParameters)        {            return ExecteNonQuery(CommandType.Text, cmdText, commandParameters);        }        #endregion        #region//GetTable方法        /// <summary>        /// 执行一条返回结果集的SqlCommand，通过一个已经存在的数据库连接        /// 使用参数数组提供参数        /// </summary>        /// <param name="connecttionString">一个现有的数据库连接</param>        /// <param name="cmdTye">SqlCommand命令类型</param>        /// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>        /// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>        /// <returns>返回一个表集合(DataTableCollection)表示查询得到的数据集</returns>        public static DataTableCollection GetTable(string connecttionString, CommandType cmdTye, string cmdText, SqlParameter[] commandParameters)        {            SqlCommand cmd = new SqlCommand();            DataSet ds = new DataSet();            using (SqlConnection conn = new SqlConnection(connecttionString))            {                PrepareCommand(cmd, conn, null, cmdTye, cmdText, commandParameters);                SqlDataAdapter adapter = new SqlDataAdapter();                adapter.SelectCommand = cmd;                adapter.Fill(ds);            }            DataTableCollection table = ds.Tables;            return table;        }        /// <summary>        /// 执行一条返回结果集的SqlCommand，通过一个已经存在的数据库连接        /// 使用参数数组提供参数        /// </summary>        /// <param name="cmdTye">SqlCommand命令类型</param>        /// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>        /// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>        /// <returns>返回一个表集合(DataTableCollection)表示查询得到的数据集</returns>        public static DataTableCollection GetTable(CommandType cmdTye, string cmdText, SqlParameter[] commandParameters)        {            return GetTable(cmdTye, cmdText, commandParameters);        }        /// <summary>        /// 存储过程专用        /// </summary>        /// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>        /// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>        /// <returns>返回一个表集合(DataTableCollection)表示查询得到的数据集</returns>        public static DataTableCollection GetTableProducts(string cmdText, SqlParameter[] commandParameters)        {            return GetTable(CommandType.StoredProcedure, cmdText, commandParameters);        }        /// <summary>        /// Sql语句专用        /// </summary>        /// <param name="cmdText"> T-SQL 语句</param>        /// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>        /// <returns>返回一个表集合(DataTableCollection)表示查询得到的数据集</returns>        public static DataTableCollection GetTableText(string cmdText, SqlParameter[] commandParameters)        {            return GetTable(CommandType.Text, cmdText, commandParameters);        }        #endregion        /// <summary>        /// 为执行命令准备参数        /// </summary>        /// <param name="cmd">SqlCommand 命令</param>        /// <param name="conn">已经存在的数据库连接</param>        /// <param name="trans">数据库事物处理</param>        /// <param name="cmdType">SqlCommand命令类型 (存储过程， T-SQL语句， 等等。)</param>        /// <param name="cmdText">Command text，T-SQL语句 例如 Select * from Products</param>        /// <param name="cmdParms">返回带参数的命令</param>        private static void PrepareCommand(SqlCommand cmd, SqlConnection conn, SqlTransaction trans, CommandType cmdType, string cmdText, SqlParameter[] cmdParms)        {            //判断数据库连接状态            if (conn.State != ConnectionState.Open)                conn.Open();            cmd.Connection = conn;            cmd.CommandText = cmdText;            //判断是否需要事物处理            if (trans != null)                cmd.Transaction = trans;            cmd.CommandType = cmdType;            if (cmdParms != null)            {                foreach (SqlParameter parm in cmdParms)                    cmd.Parameters.Add(parm);            }        }        /// <summary>        /// Execute a SqlCommand that returns a resultset against the database specified in the connection string         /// using the provided parameters.        /// </summary>        /// <param name="connectionString">一个有效的数据库连接字符串</param>        /// <param name="cmdType">SqlCommand命令类型 (存储过程， T-SQL语句， 等等。)</param>        /// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>        /// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>        /// <returns>A SqlDataReader containing the results</returns>        public static SqlDataReader ExecuteReader(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)        {            SqlCommand cmd = new SqlCommand();            SqlConnection conn = new SqlConnection(connectionString);            // we use a try/catch here because if the method throws an exception we want to             // close the connection throw code, because no datareader will exist, hence the             // commandBehaviour.CloseConnection will not work            try            {                PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);                SqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);                cmd.Parameters.Clear();                return rdr;            }            catch            {                conn.Close();                throw;            }        }        #region//ExecuteDataSet方法        /// <summary>        /// return a dataset        /// </summary>        /// <param name="connectionString">一个有效的数据库连接字符串</param>        /// <param name="cmdType">SqlCommand命令类型 (存储过程， T-SQL语句， 等等。)</param>        /// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>        /// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>        /// <returns>return a dataset</returns>        public static DataSet ExecuteDataSet(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)        {            SqlConnection conn = new SqlConnection(connectionString);            SqlCommand cmd = new SqlCommand();            try            {                PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);                SqlDataAdapter da = new SqlDataAdapter();                DataSet ds = new DataSet();                da.SelectCommand = cmd;                da.Fill(ds);                return ds;            }            catch            {                conn.Close();                throw;            }        }        /// <summary>        /// 返回一个DataSet        /// </summary>        /// <param name="cmdType">SqlCommand命令类型 (存储过程， T-SQL语句， 等等。)</param>        /// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>        /// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>        /// <returns>return a dataset</returns>        public static DataSet ExecuteDataSet(CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)        {            return ExecuteDataSet(connectionString, cmdType, cmdText, commandParameters);        }        /// <summary>        /// 返回一个DataSet        /// </summary>        /// <param name="cmdText">存储过程的名字</param>        /// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>        /// <returns>return a dataset</returns>        public static DataSet ExecuteDataSetProducts(string cmdText, params SqlParameter[] commandParameters)        {            return ExecuteDataSet(connectionString, CommandType.StoredProcedure, cmdText, commandParameters);        }        /// <summary>        /// 返回一个DataSet        /// </summary>        /// <param name="cmdText">T-SQL 语句</param>        /// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>        /// <returns>return a dataset</returns>        public static DataSet ExecuteDataSetText(string cmdText, params SqlParameter[] commandParameters)        {            return ExecuteDataSet(connectionString, CommandType.Text, cmdText, commandParameters);        }        public static DataView ExecuteDataSet(string connectionString, string sortExpression, string direction, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)        {            SqlConnection conn = new SqlConnection(connectionString);            SqlCommand cmd = new SqlCommand();            try            {                PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);                SqlDataAdapter da = new SqlDataAdapter();                DataSet ds = new DataSet();                da.SelectCommand = cmd;                da.Fill(ds);                DataView dv = ds.Tables[0].DefaultView;                dv.Sort = sortExpression + " " + direction;                return dv;            }            catch            {                conn.Close();                throw;            }        }        #endregion        #region // ExecuteScalar方法        /// <summary>        /// 返回第一行的第一列        /// </summary>        /// <param name="cmdType">SqlCommand命令类型 (存储过程， T-SQL语句， 等等。)</param>        /// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>        /// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>        /// <returns>返回一个对象</returns>        public static object ExecuteScalar(CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)        {            return ExecuteScalar(SqlHelper.connectionString, cmdType, cmdText, commandParameters);        }        /// <summary>        /// 返回第一行的第一列存储过程专用        /// </summary>        /// <param name="cmdText">存储过程的名字</param>        /// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>        /// <returns>返回一个对象</returns>        public static object ExecuteScalarProducts(string cmdText, params SqlParameter[] commandParameters)        {            return ExecuteScalar(SqlHelper.connectionString, CommandType.StoredProcedure, cmdText, commandParameters);        }        /// <summary>        /// 返回第一行的第一列Sql语句专用        /// </summary>        /// <param name="cmdText">者 T-SQL 语句</param>        /// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>        /// <returns>返回一个对象</returns>        public static object ExecuteScalarText(string cmdText, params SqlParameter[] commandParameters)        {            return ExecuteScalar(SqlHelper.connectionString, CommandType.Text, cmdText, commandParameters);        }        /// <summary>        /// Execute a SqlCommand that returns the first column of the first record against the database specified in the connection string         /// using the provided parameters.        /// </summary>        /// <remarks>        /// e.g.:          ///  Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));        /// </remarks>        /// <param name="connectionString">一个有效的数据库连接字符串</param>        /// <param name="cmdType">SqlCommand命令类型 (存储过程， T-SQL语句， 等等。)</param>        /// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>        /// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>        /// <returns>An object that should be converted to the expected type using Convert.To{Type}</returns>        public static object ExecuteScalar(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)        {            SqlCommand cmd = new SqlCommand();            using (SqlConnection connection = new SqlConnection(connectionString))            {                PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);                object val = cmd.ExecuteScalar();                cmd.Parameters.Clear();                return val;            }        }        /// <summary>        /// Execute a SqlCommand that returns the first column of the first record against an existing database connection         /// using the provided parameters.        /// </summary>        /// <remarks>        /// e.g.:          ///  Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));        /// </remarks>        /// <param name="connectionString">一个有效的数据库连接字符串</param>        /// <param name="cmdType">SqlCommand命令类型 (存储过程， T-SQL语句， 等等。)</param>        /// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>        /// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>        /// <returns>An object that should be converted to the expected type using Convert.To{Type}</returns>        public static object ExecuteScalar(SqlConnection connection, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)        {            SqlCommand cmd = new SqlCommand();            PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);            object val = cmd.ExecuteScalar();            cmd.Parameters.Clear();            return val;        }        #endregion        /// <summary>        /// add parameter array to the cache        /// </summary>        /// <param name="cacheKey">Key to the parameter cache</param>        /// <param name="cmdParms">an array of SqlParamters to be cached</param>        public static void CacheParameters(string cacheKey, params SqlParameter[] commandParameters)        {            parmCache[cacheKey] = commandParameters;        }        /// <summary>        /// Retrieve cached parameters        /// </summary>        /// <param name="cacheKey">key used to lookup parameters</param>        /// <returns>Cached SqlParamters array</returns>        public static SqlParameter[] GetCachedParameters(string cacheKey)        {            SqlParameter[] cachedParms = (SqlParameter[])parmCache[cacheKey];            if (cachedParms == null)                return null;            SqlParameter[] clonedParms = new SqlParameter[cachedParms.Length];            for (int i = 0, j = cachedParms.Length; i < j; i++)                clonedParms[i] = (SqlParameter)((ICloneable)cachedParms[i]).Clone();            return clonedParms;        }        /// <summary>        /// 检查是否存在        /// </summary>        /// <param name="strSql">Sql语句</param>        /// <returns>bool结果</returns>        public static bool Exists(string strSql)        {            int cmdresult = Convert.ToInt32(ExecuteScalar(connectionString, CommandType.Text, strSql, null));            if (cmdresult == 0)            {                return false;            }            else            {                return true;            }        }        /// <summary>        /// 检查是否存在        /// </summary>        /// <param name="strSql">Sql语句</param>        /// <param name="cmdParms">参数</param>        /// <returns>bool结果</returns>        public static bool Exists(string strSql, params SqlParameter[] cmdParms)        {            int cmdresult = Convert.ToInt32(ExecuteScalar(connectionString, CommandType.Text, strSql, cmdParms));            if (cmdresult == 0)            {                return false;            }            else            {                return true;            }        }    }}