using System; 
using System.Data; 
using System.Xml; 
using System.Data.SqlClient; 
using System.Collections; 
using System.Configuration;

namespace BookDAL 
{ 
    /// <summary> 
    /// SqlServer数据访问帮助类 
    /// </summary> 
    public sealed class SqlHelper 
    { 
        #region 私有构造函数和方法

        private SqlHelper() { }

        /// <summary> 
        /// 将SqlParameter参数数组(参数值)分配给SqlCommand命令. 
        /// 这个方法将给任何一个参数分配DBNull.Value; 
        /// 该操作将阻止默认值的使用. 
        /// </summary> 
        /// <param name="command">命令名</param> 
        /// <param name="commandParameters">SqlParameters数组</param> 
        private static void AttachParameters(SqlCommand command, SqlParameter[] commandParameters) 
        { 
            if (command == null) throw new ArgumentNullException("command"); 
            if (commandParameters != null) 
            { 
                foreach (SqlParameter p in commandParameters) 
                { 
                    if (p != null) 
                    { 
                        // 检查未分配值的输出参数,将其分配以DBNull.Value. 
                        if ((p.Direction == ParameterDirection.InputOutput || p.Direction == ParameterDirection.Input) && 
                            (p.Value == null)) 
                        { 
                            p.Value = DBNull.Value; 
                        } 
                        command.Parameters.Add(p); 
                    } 
                } 
            } 
        }

        /// <summary> 
        /// 将DataRow类型的列值分配到SqlParameter参数数组. 
        /// </summary> 
        /// <param name="commandParameters">要分配值的SqlParameter参数数组</param> 
        /// <param name="dataRow">将要分配给存储过程参数的DataRow</param> 
        private static void AssignParameterValues(SqlParameter[] commandParameters, DataRow dataRow) 
        { 
            if ((commandParameters == null) || (dataRow == null)) 
            { 
                return; 
            }

            int i = 0; 
            // 设置参数值 
            foreach (SqlParameter commandParameter in commandParameters) 
            { 
                // 创建参数名称,如果不存在,只抛出一个异常. 
                if (commandParameter.ParameterName == null || 
                    commandParameter.ParameterName.Length <= 1) 
                    throw new Exception( 
                        string.Format("请提供参数{0}一个有效的名称{1}.", i, commandParameter.ParameterName)); 
                // 从dataRow的表中获取为参数数组中数组名称的列的索引. 
                // 如果存在和参数名称相同的列,则将列值赋给当前名称的参数. 
                if (dataRow.Table.Columns.IndexOf(commandParameter.ParameterName.Substring(1)) != -1) 
                    commandParameter.Value = dataRow[commandParameter.ParameterName.Substring(1)]; 
                i++; 
            } 
        }

        /// <summary> 
        /// 将一个对象数组分配给SqlParameter参数数组. 
        /// </summary> 
        /// <param name="commandParameters">要分配值的SqlParameter参数数组</param> 
        /// <param name="parameterValues">将要分配给存储过程参数的对象数组</param> 
        private static void AssignParameterValues(SqlParameter[] commandParameters, object[] parameterValues) 
        { 
            if ((commandParameters == null) || (parameterValues == null)) 
            { 
                return; 
            }

            // 确保对象数组个数与参数个数匹配,如果不匹配,抛出一个异常. 
            if (commandParameters.Length != parameterValues.Length) 
            { 
                throw new ArgumentException("参数值个数与参数不匹配."); 
            }

            // 给参数赋值 
            for (int i = 0, j = commandParameters.Length; i < j; i++) 
            { 
                // If the current array value derives from IDbDataParameter, then assign its Value property 
                if (parameterValues[i] is IDbDataParameter) 
                { 
                    IDbDataParameter paramInstance = (IDbDataParameter)parameterValues[i]; 
                    if (paramInstance.Value == null) 
                    { 
                        commandParameters[i].Value = DBNull.Value; 
                    } 
                    else 
                    { 
                        commandParameters[i].Value = paramInstance.Value; 
                    } 
                } 
                else if (parameterValues[i] == null) 
                { 
                    commandParameters[i].Value = DBNull.Value; 
                } 
                else 
                { 
                    commandParameters[i].Value = parameterValues[i]; 
                } 
            } 
        }

        /// <summary> 
        /// 预处理用户提供的命令,数据库连接/事务/命令类型/参数 
        /// </summary> 
        /// <param name="command">要处理的SqlCommand</param> 
        /// <param name="connection">数据库连接</param> 
        /// <param name="transaction">一个有效的事务或者是null值</param> 
        /// <param name="commandType">命令类型 (存储过程,命令文本, 其它.)</param> 
        /// <param name="commandText">存储过程名或都T-SQL命令文本</param> 
        /// <param name="commandParameters">和命令相关联的SqlParameter参数数组,如果没有参数为'null'</param> 
        /// <param name="mustCloseConnection"><c>true</c> 如果连接是打开的,则为true,其它情况下为false.</param> 
        private static void PrepareCommand(SqlCommand command, SqlConnection connection, SqlTransaction transaction, CommandType commandType, string commandText, SqlParameter[] commandParameters, out bool mustCloseConnection) 
        { 
            if (command == null) throw new ArgumentNullException("command"); 
            if (commandText == null || commandText.Length == 0) throw new ArgumentNullException("commandText");

            // If the provided connection is not open, we will open it 
            if (connection.State != ConnectionState.Open) 
            { 
                mustCloseConnection = true; 
                connection.Open(); 
            } 
            else 
            { 
                mustCloseConnection = false; 
            }

            // 给命令分配一个数据库连接. 
            command.Connection = connection;

            // 设置命令文本(存储过程名或SQL语句) 
            command.CommandText = commandText;

            // 分配事务 
            if (transaction != null) 
            { 
                if (transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction"); 
                command.Transaction = transaction; 
            }

            // 设置命令类型. 
            command.CommandType = commandType;

            // 分配命令参数 
            if (commandParameters != null) 
            { 
                AttachParameters(command, commandParameters); 
            } 
            return; 
        }

        #endregion 私有构造函数和方法结束

        #region 数据库连接 
        /// <summary> 
        /// 一个有效的数据库连接字符串 
        /// </summary> 
        /// <returns></returns> 
        public static string GetConnSting() 
        { 
            return ConfigurationManager.ConnectionStrings["ConStr"].ConnectionString; 
        } 
        /// <summary> 
        /// 一个有效的数据库连接对象 
        /// </summary> 
        /// <returns></returns> 
        public static SqlConnection GetConnection() 
        { 
            SqlConnection Connection = new SqlConnection(SqlHelper.GetConnSting()); 
            return Connection; 
        } 
        #endregion

        #region ExecuteNonQuery命令

        /// <summary> 
        /// 执行指定连接字符串,类型的SqlCommand. 
        /// </summary> 
        /// <remarks> 
        /// 示例:  
        ///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders"); 
        /// </remarks> 
        /// <param name="connectionString">一个有效的数据库连接字符串</param> 
        /// <param name="commandType">命令类型 (存储过程,命令文本, 其它.)</param> 
        /// <param name="commandText">存储过程名称或SQL语句</param> 
        /// <returns>返回命令影响的行数</returns> 
        public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText) 
        { 
            return ExecuteNonQuery(connectionString, commandType, commandText, (SqlParameter[])null); 
        }

        /// <summary> 
        /// 执行指定连接字符串,类型的SqlCommand.如果没有提供参数,不返回结果. 
        /// </summary> 
        /// <remarks> 
        /// 示例:  
        ///  int result = ExecuteNonQuery(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="commandType">命令类型 (存储过程,命令文本, 其它.)</param> 
        /// <param name="commandText">存储过程名称或SQL语句</param> 
        /// <param name="commandParameters">SqlParameter参数数组</param> 
        /// <returns>返回命令影响的行数</returns> 
        public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters) 
        { 
            if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");

            using (SqlConnection connection = new SqlConnection(connectionString)) 
            { 
                connection.Open();

                return ExecuteNonQuery(connection, commandType, commandText, commandParameters); 
            } 
        }

        /// <summary> 
        /// 执行指定连接字符串的存储过程,将对象数组的值赋给存储过程参数, 
        /// 此方法需要在参数缓存方法中探索参数并生成参数. 
        /// </summary> 
        /// <remarks> 
        /// 这个方法没有提供访问输出参数和返回值. 
        /// 示例:  
        ///  int result = ExecuteNonQuery(connString, "PublishOrders", 24, 36); 
        /// </remarks> 
        /// <param name="connectionString">一个有效的数据库连接字符串/param> 
        /// <param name="spName">存储过程名称</param> 
        /// <param name="parameterValues">分配到存储过程输入参数的对象数组</param> 
        /// <returns>返回受影响的行数</returns> 
        public static int ExecuteNonQuery(string connectionString, string spName, params object[] parameterValues) 
        { 
            if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString"); 
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

            // 如果存在参数值 
            if ((parameterValues != null) && (parameterValues.Length > 0)) 
            { 
                // 从探索存储过程参数(加载到缓存)并分配给存储过程参数数组. 
                SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);

                // 给存储过程参数赋值 
                AssignParameterValues(commandParameters, parameterValues);

                return ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName, commandParameters); 
            } 
            else 
            { 
                // 没有参数情况下 
                return ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName); 
            } 
        }

        /// <summary> 
        /// 执行指定数据库连接对象的命令 
        /// </summary> 
        /// <remarks> 
        /// 示例:  
        ///  int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders"); 
        /// </remarks> 
        /// <param name="connection">一个有效的数据库连接对象</param> 
        /// <param name="commandType">命令类型(存储过程,命令文本或其它.)</param> 
        /// <param name="commandText">存储过程名称或T-SQL语句</param> 
        /// <returns>返回影响的行数</returns> 
        public static int ExecuteNonQuery(SqlConnection connection, CommandType commandType, string commandText) 
        { 
            return ExecuteNonQuery(connection, commandType, commandText, (SqlParameter[])null); 
        }

        /// <summary> 
        /// 执行指定数据库连接对象的命令 
        /// </summary> 
        /// <remarks> 
        /// 示例:  
        ///  int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24)); 
        /// </remarks> 
        /// <param name="connection">一个有效的数据库连接对象</param> 
        /// <param name="commandType">命令类型(存储过程,命令文本或其它.)</param> 
        /// <param name="commandText">T存储过程名称或T-SQL语句</param> 
        /// <param name="commandParameters">SqlParamter参数数组</param> 
        /// <returns>返回影响的行数</returns> 
        public static int ExecuteNonQuery(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters) 
        { 
            if (connection == null) throw new ArgumentNullException("connection");

            // 创建SqlCommand命令,并进行预处理 
            SqlCommand cmd = new SqlCommand(); 
            bool mustCloseConnection = false; 
            PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters, out mustCloseConnection);

            // Finally, execute the command 
            int retval = cmd.ExecuteNonQuery();

            // 清除参数,以便再次使用. 
            cmd.Parameters.Clear(); 
            if (mustCloseConnection) 
                connection.Close(); 
            return retval; 
        }

        /// <summary> 
        /// 执行指定数据库连接对象的命令,将对象数组的值赋给存储过程参数. 
        /// </summary> 
        /// <remarks> 
        /// 此方法不提供访问存储过程输出参数和返回值 
        /// 示例:  
        ///  int result = ExecuteNonQuery(conn, "PublishOrders", 24, 36); 
        /// </remarks> 
        /// <param name="connection">一个有效的数据库连接对象</param> 
        /// <param name="spName">存储过程名</param> 
        /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param> 
        /// <returns>返回影响的行数</returns> 
        public static int ExecuteNonQuery(SqlConnection connection, string spName, params object[] parameterValues) 
        { 
            if (connection == null) throw new ArgumentNullException("connection"); 
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

            // 如果有参数值 
            if ((parameterValues != null) && (parameterValues.Length > 0)) 
            { 
                // 从缓存中加载存储过程参数 
                SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);

                // 给存储过程分配参数值 
                AssignParameterValues(commandParameters, parameterValues);

                return ExecuteNonQuery(connection, CommandType.StoredProcedure, spName, commandParameters); 
            } 
            else 
            { 
                return ExecuteNonQuery(connection, CommandType.StoredProcedure, spName); 
            } 
        }

        /// <summary> 
        /// 执行带事务的SqlCommand. 
        /// </summary> 
        /// <remarks> 
        /// 示例.:  
        ///  int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "PublishOrders"); 
        /// </remarks> 
        /// <param name="transaction">一个有效的数据库连接对象</param> 
        /// <param name="commandType">命令类型(存储过程,命令文本或其它.)</param> 
        /// <param name="commandText">存储过程名称或T-SQL语句</param> 
        /// <returns>返回影响的行数/returns> 
        public static int ExecuteNonQuery(SqlTransaction transaction, CommandType commandType, string commandText) 
        { 
            return ExecuteNonQuery(transaction, commandType, commandText, (SqlParameter[])null); 
        }

        /// <summary> 
        /// 执行带事务的SqlCommand(指定参数). 
        /// </summary> 
        /// <remarks> 
        /// 示例:  
        ///  int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24)); 
        /// </remarks> 
        /// <param name="transaction">一个有效的数据库连接对象</param> 
        /// <param name="commandType">命令类型(存储过程,命令文本或其它.)</param> 
        /// <param name="commandText">存储过程名称或T-SQL语句</param> 
        /// <param name="commandParameters">SqlParamter参数数组</param> 
        /// <returns>返回影响的行数</returns> 
        public static int ExecuteNonQuery(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters) 
        { 
            if (transaction == null) throw new ArgumentNullException("transaction"); 
            if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");

            // 预处理 
            SqlCommand cmd = new SqlCommand(); 
            bool mustCloseConnection = false; 
            PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection);

            // 执行 
            int retval = cmd.ExecuteNonQuery();

            // 清除参数集,以便再次使用. 
            cmd.Parameters.Clear(); 
            return retval; 
        }

        /// <summary> 
        /// 执行带事务的SqlCommand(指定参数值). 
        /// </summary> 
        /// <remarks> 
        /// 此方法不提供访问存储过程输出参数和返回值 
        /// 示例:  
        ///  int result = ExecuteNonQuery(conn, trans, "PublishOrders", 24, 36); 
        /// </remarks> 
        /// <param name="transaction">一个有效的数据库连接对象</param> 
        /// <param name="spName">存储过程名</param> 
        /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param> 
        /// <returns>返回受影响的行数</returns> 
        public static int ExecuteNonQuery(SqlTransaction transaction, string spName, params object[] parameterValues) 
        { 
            if (transaction == null) throw new ArgumentNullException("transaction"); 
            if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction"); 
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

            // 如果有参数值 
            if ((parameterValues != null) && (parameterValues.Length > 0)) 
            { 
                // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. () 
                SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

                // 给存储过程参数赋值 
                AssignParameterValues(commandParameters, parameterValues);

                // 调用重载方法 
                return ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName, commandParameters); 
            } 
            else 
            { 
                // 没有参数值 
                return ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName); 
            } 
        }

        #endregion ExecuteNonQuery方法结束

        #region ExecuteDataset方法

        /// <summary> 
        /// 执行指定数据库连接字符串的命令,返回DataSet. 
        /// </summary> 
        /// <remarks> 
        /// 示例: