SQL Server 数据库操作类

    /// <summary>
    /// SQLServerHelper的摘要说明。
    /// </summary>
    public class SQLServerHelper
    {
        public static string connectionString = ConfigurationManager.ConnectionStrings["SQLConnString"].ConnectionString;

        #region private utility methods & constructors

        //Since this class provides only static methods, make the default constructor private to prevent
        //instances from being created with "new SqlHelper()".
        private SQLServerHelper()
        {

        }

        /// <summary>
        /// This method is used to attach array of SqlParameters to a SqlCommand.
        ///
        /// This method will assign a value of DbNull to any parameter with a direction of
        /// InputOutput and a value of null.
        ///
        /// This behavior will prevent default values from being used, but
        /// this will be the less common case than an intended pure output parameter (derived as InputOutput)
        /// where the user provided no input value.
        /// </summary>
        /// <param name="command">The command to which the parameters will be added</param>
        /// <param name="commandParameters">an array of SqlParameters tho be added to command</param>
        private static void AttachParameters(SqlCommand command, SqlParameter[] commandParameters)
        {
            try
            {
                foreach (SqlParameter p in commandParameters)
                {
                    //check for derived output value with no value assigned
                    if ((p.Direction == ParameterDirection.InputOutput) && (p.Value == null))
                    {
                        p.Value = DBNull.Value;
                    }
                    else
                    {
                        if (p.Value == null)
                        {
                            p.Value = DBNull.Value;
                        }
                    }

                    command.Parameters.Add(p);
                }
            }
            catch (Exception ex)
            {
                Utils.WriteLogFile(ex.Message.ToString(), "异常日志");
            }
        }

        /// <summary>
        /// This method assigns an array of values to an array of SqlParameters.
        /// </summary>
        /// <param name="commandParameters">array of SqlParameters to be assigned values</param>
        /// <param name="parameterValues">array of Components holding the values to be assigned</param>
        private static void AssignParameterValues(SqlParameter[] commandParameters, object[] parameterValues)
        {
            try
            {
                if ((commandParameters == null) || (parameterValues == null))
                {
                    //do nothing if we get no data
                    return;
                }

                // we must have the same number of values as we pave parameters to put them in
                if (commandParameters.Length != parameterValues.Length)
                {
                    throw new ArgumentException("Parameter count does not match Parameter Value count.");
                }

                //iterate through the SqlParameters, assigning the values from the corresponding position in the
                //value array
                for (int i = 0, j = commandParameters.Length; i < j; i++)
                {
                    commandParameters[i].Value = parameterValues[i];
                }
            }
            catch (Exception ex)
            {
                Utils.WriteLogFile(ex.Message.ToString(), "异常日志");
            }

        }

        /// <summary>
        /// This method opens (if necessary) and assigns a connection, transaction, command type and parameters
        /// to the provided command.
        /// </summary>
        /// <param name="command">the SqlCommand to be prepared</param>
        /// <param name="connection">a valid SqlConnection, on which to execute this command</param>
        /// <param name="transaction">a valid SqlTransaction, or 'null'</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParameters to be associated with the command or 'null' if no parameters are required</param>
        private static void PrepareCommand(SqlCommand command, SqlConnection connection, SqlTransaction transaction,
                                           CommandType commandType, string commandText, SqlParameter[] commandParameters)
        {
            try
            {
                //if the provided connection is not open, we will open it
                if (connection.State != ConnectionState.Open)
                {
                    connection.Open();
                }

                //associate the connection with the command
                command.Connection = connection;

                //set the command text (stored procedure name or SQL statement)
                command.CommandText = commandText;

                //if we were provided a transaction, assign it.
                if (transaction != null)
                {
                    command.Transaction = transaction;
                }

                //set the command type
                command.CommandType = commandType;

                //attach the command parameters if they are provided
                if (commandParameters != null)
                {
                    AttachParameters(command, commandParameters);
                }
            }
            catch (Exception ex)
            {
                Utils.WriteLogFile(ex.Message.ToString(), "异常日志");
            }

            return;
        }

        #endregion private utility methods & constructors

        #region DataHelpers

        public static string CheckNull(object obj)
        {
            return (string)obj;
        }

        public static string CheckNull(DBNull obj)
        {
            return null;
        }

        #endregion

        #region AddParameters

        public static object CheckForNullString(string text)
        {
            if (text == null || text.Trim().Length == 0)
            {
                return System.DBNull.Value;
            }
            else
            {
                return text;
            }
        }

        public static SqlParameter MakeInParam(string ParamName, object Value)
        {
            return new SqlParameter(ParamName, Value);
        }

        /// <summary>
        /// Make input param.
        /// </summary>
        /// <param name="ParamName">Name of param.</param>
        /// <param name="DbType">Param type.</param>
        /// <param name="Size">Param size.</param>
        /// <param name="Value">Param value.</param>
        /// <returns>New parameter.</returns>
        public static SqlParameter MakeInParam(string ParamName, SqlDbType DbType, int Size, object Value)
        {
            return MakeParam(ParamName, DbType, Size, ParameterDirection.Input, Value);
        }

        /// <summary>
        /// Make input param.
        /// </summary>
        /// <param name="ParamName">Name of param.</param>
        /// <param name="DbType">Param type.</param>
        /// <param name="Size">Param size.</param>
        /// <returns>New parameter.</returns>
        public static SqlParameter MakeOutParam(string ParamName, SqlDbType DbType, int Size)
        {
            return MakeParam(ParamName, DbType, Size, ParameterDirection.Output, null);
        }

        /// <summary>
        /// Make stored procedure param.
        /// </summary>
        /// <param name="ParamName">Name of param.</param>
        /// <param name="DbType">Param type.</param>
        /// <param name="Size">Param size.</param>
        /// <param name="Direction">Parm direction.</param>
        /// <param name="Value">Param value.</param>
        /// <returns>New parameter.</returns>
        public static SqlParameter MakeParam(string ParamName, SqlDbType DbType, Int32 Size,
                                             ParameterDirection Direction, object Value)
        {
            SqlParameter param;

            if (Size > 0)
                param = new SqlParameter(ParamName, DbType, Size);
            else
                param = new SqlParameter(ParamName, DbType);

            param.Direction = Direction;
            if (!(Direction == ParameterDirection.Output && Value == null))
                param.Value = Value;

            return param;
        }

        #endregion

        #region ExecuteNonQuery

        /// <summary>
        /// Execute a SqlCommand (that returns no resultset and takes no parameters) against the database specified in
        /// the connection string.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders");
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>an int representing the number of rows affected by the command</returns>
        public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteNonQuery(connectionString, commandType, commandText, (SqlParameter[])null);
        }

        public static int ExecuteNonQuery(CommandType commandType, string commandText,
                                          params SqlParameter[] commandParameters)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteNonQuery(connectionString, commandType, commandText, commandParameters);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns no resultset) against the database specified in the connection string
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("?prodid", 24));
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>an int representing the number of rows affected by the command</returns>
        public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText,
                                          params SqlParameter[] commandParameters)
        {
            //create & open a SqlConnection, and dispose of it after we are done.
            using (SqlConnection cn = new SqlConnection(connectionString))
            {
                cn.Open();
                //call the overload that takes a connection in place of the connection string
                return ExecuteNonQuery(cn, commandType, commandText, commandParameters);
            }
        }

        /// <summary>
        /// Execute a SqlCommand (that returns no resultset and takes no parameters) against the provided SqlConnection.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders");
        /// </remarks>
        /// <param name="connection">a valid SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>an int representing the number of rows affected by the command</returns>
        public static int ExecuteNonQuery(SqlConnection connection, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteNonQuery(connection, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns no resultset) against the specified SqlConnection
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("?prodid", 24));
        /// </remarks>
        /// <param name="connection">a valid SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>an int representing the number of rows affected by the command</returns>
        public static int ExecuteNonQuery(SqlConnection connection, CommandType commandType, string commandText,
                                          params SqlParameter[] commandParameters)
        {
            SqlTransaction sqltran;
            sqltran = connection.BeginTransaction();
            int retval = -1;
            try
            {
                //create a command and prepare it for execution
                SqlCommand cmd = new SqlCommand();

                PrepareCommand(cmd, connection, sqltran, commandType, commandText, commandParameters);
                //cmd.CommandTimeout = 5;
                //finally, execute the command.
                retval = cmd.ExecuteNonQuery();
                sqltran.Commit();
                // detach the SqlParameters from the command object, so they can be used again.
                cmd.Parameters.Clear();

            }
            catch (Exception ex)
            {
                try
                {
                    sqltran.Rollback();
                }
                catch (Exception e)
                {
                }

                string str = string.Empty;
                for (int i = 0; i < commandParameters.Length - 1; i++)
                {
                    str += commandParameters[i].ParameterName + "=" + commandParameters[i].Value.ToString() + ",";
                }
                Utils.WriteLogFile("执行" + commandText + "时" + ex.Message.ToString() + "参数值为:" + str, "异常日志");
                retval = -1;
            }
            finally
            {
                connection.Close();
            }

            return retval;
        }

        /// <summary>
        /// Execute a SqlCommand (that returns no resultset and takes no parameters) against the provided SqlTransaction.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "PublishOrders");
        /// </remarks>
        /// <param name="transaction">a valid SqlTransaction</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>an int representing the number of rows affected by the command</returns>
        public static int ExecuteNonQuery(SqlTransaction transaction, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteNonQuery(transaction, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns no resultset) against the specified SqlTransaction
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("?prodid", 24));
        /// </remarks>
        /// <param name="transaction">a valid SqlTransaction</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>an int representing the number of rows affected by the command</returns>
        public static int ExecuteNonQuery(SqlTransaction transaction, CommandType commandType, string commandText,
                                          params SqlParameter[] commandParameters)
        {
            try
            {
                //create a command and prepare it for execution
                SqlCommand cmd = new SqlCommand();
                PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters);
                //cmd.CommandTimeout = 5;
                //finally, execute the command.
                int retval = cmd.ExecuteNonQuery();

                // detach the SqlParameters from the command object, so they can be used again.
                cmd.Parameters.Clear();
                return retval;
            }
            catch (Exception ex)
            {
                string str = string.Empty;
                if (commandParameters != null)
                {
                    for (int i = 0; i < commandParameters.Length - 1; i++)
                    {
                        str += commandParameters[i].ParameterName + "=" + commandParameters[i].Value.ToString() + ",";
                    }
                }
                Utils.WriteLogFile("执行" + commandText + "时" + ex.Message.ToString() + "参数值为:" + str, "异常日志");
                return -1;
            }
            finally
            {
                //transaction.Connection.Close();
            }
        }

        #endregion ExecuteNonQuery

        #region ExecuteDataSet

        public static DataSet ExecuteDataset(CommandType commandType, string commandText,
                                             params SqlParameter[] commandParameters)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteDataset(connectionString, commandType, commandText, commandParameters);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the database specified in
        /// the connection string.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  DataSet ds = ExecuteDataset(connString, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>a dataset containing the resultset generated by the command</returns>
        public static DataSet ExecuteDataset(string connectionString, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteDataset(connectionString, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset) against the database specified in the connection string
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  DataSet ds = ExecuteDataset(connString, CommandType.StoredProcedure, "GetOrders", new SqlParameter("?prodid", 24));
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>a dataset containing the resultset generated by the command</returns>
        public static DataSet ExecuteDataset(string connectionString, CommandType commandType, string commandText,
                                             params SqlParameter[] commandParameters)
        {
            //create & open a SqlConnection, and dispose of it after we are done.
            using (SqlConnection cn = new SqlConnection(connectionString))
            {
                cn.Open();

                //call the overload that takes a connection in place of the connection string
                return ExecuteDataset(cn, commandType, commandText, commandParameters);
            }
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the provided SqlConnection.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  DataSet ds = ExecuteDataset(conn, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="connection">a valid SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>a dataset containing the resultset generated by the command</returns>
        public static DataSet ExecuteDataset(SqlConnection connection, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteDataset(connection, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset) against the specified SqlConnection
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  DataSet ds = ExecuteDataset(conn, CommandType.StoredProcedure, "GetOrders", new SqlParameter("?prodid", 24));
        /// </remarks>
        /// <param name="connection">a valid SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>a dataset containing the resultset generated by the command</returns>
        public static DataSet ExecuteDataset(SqlConnection connection, CommandType commandType, string commandText,
                                             params SqlParameter[] commandParameters)
        {
            try
            {
                //create a command and prepare it for execution
                SqlCommand cmd = new SqlCommand();
                PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters);

                //create the DataAdapter & DataSet
                SqlDataAdapter da = new SqlDataAdapter(cmd);
                DataSet ds = new DataSet();

                //fill the DataSet using default values for DataTable names, etc.
                da.Fill(ds);

                // detach the SqlParameters from the command object, so they can be used again.
                cmd.Parameters.Clear();
                //return the dataset
                return ds;
            }
            catch (Exception ex)
            {
                Utils.WriteLogFile("执行" + commandText + "时" + ex.Message.ToString(), "异常日志");
            }
            finally
            {
                connection.Close();
            }
            return null;
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the provided SqlTransaction.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  DataSet ds = ExecuteDataset(trans, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="transaction">a valid SqlTransaction</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>a dataset containing the resultset generated by the command</returns>
        public static DataSet ExecuteDataset(SqlTransaction transaction, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteDataset(transaction, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset) against the specified SqlTransaction
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  DataSet ds = ExecuteDataset(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("?prodid", 24));
        /// </remarks>
        /// <param name="transaction">a valid SqlTransaction</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>a dataset containing the resultset generated by the command</returns>
        public static DataSet ExecuteDataset(SqlTransaction transaction, CommandType commandType, string commandText,
                                             params SqlParameter[] commandParameters)
        {
            try
            {
                //create a command and prepare it for execution
                SqlCommand cmd = new SqlCommand();
                PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters);

                //create the DataAdapter & DataSet
                SqlDataAdapter da = new SqlDataAdapter(cmd);
                DataSet ds = new DataSet();

                //fill the DataSet using default values for DataTable names, etc.
                da.Fill(ds);

                // detach the SqlParameters from the command object, so they can be used again.
                cmd.Parameters.Clear();

                //return the dataset
                return ds;
            }
            catch (Exception ex)
            {
                transaction.Connection.Close();
                Utils.WriteLogFile("执行" + commandText + "时" + ex.Message.ToString(), "异常日志");
            }
            return null;
        }

        #endregion ExecuteDataSet

        #region ExecuteDataTable

        public static DataTable ExecuteDataTable(CommandType commandType, string commandText)
        {
            return ExecuteDataTable(connectionString, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the database specified in
        /// the connection string.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  DataTable dt = ExecuteDataTable(connString, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>a DataTable containing the resultset generated by the command</returns>
        public static DataTable ExecuteDataTable(string connectionString, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteDataTable(connectionString, commandType, commandText, (SqlParameter[])null);
        }

        public static DataTable ExecuteDataTable(CommandType commandType, string commandText,
                                                 params SqlParameter[] commandParameters)
        {
            //create & open a SqlConnection, and dispose of it after we are done.
            using (SqlConnection cn = new SqlConnection(connectionString))
            {
                cn.Open();

                //call the overload that takes a connection in place of the connection string
                return ExecuteDataTable(cn, commandType, commandText, commandParameters);
            }
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset) against the database specified in the connection string
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  DataTable dt = ExecuteDataTable(connString, CommandType.StoredProcedure, "GetOrders", new SqlParameter("?prodid", 24));
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>a DataTable containing the resultset generated by the command</returns>
        public static DataTable ExecuteDataTable(string connectionString, CommandType commandType, string commandText,
                                                 params SqlParameter[] commandParameters)
        {
            //create & open a SqlConnection, and dispose of it after we are done.
            using (SqlConnection cn = new SqlConnection(connectionString))
            {
                cn.Open();

                //call the overload that takes a connection in place of the connection string
                return ExecuteDataTable(cn, commandType, commandText, commandParameters);
            }
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the provided SqlConnection.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  DataTable dt = ExecuteDataTable(conn, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="connection">a valid SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>a DataTable containing the resultset generated by the command</returns>
        public static DataTable ExecuteDataTable(SqlConnection connection, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteDataTable(connection, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset) against the specified SqlConnection
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  DataTable dt = ExecuteDataTable(conn, CommandType.StoredProcedure, "GetOrders", new SqlParameter("?prodid", 24));
        /// </remarks>
        /// <param name="connection">a valid SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>a DataTable containing the resultset generated by the command</returns>
        public static DataTable ExecuteDataTable(SqlConnection connection, CommandType commandType, string commandText,
                                                 params SqlParameter[] commandParameters)
        {
            try
            {
                //create a command and prepare it for execution
                SqlCommand cmd = new SqlCommand();
                cmd.CommandTimeout = 140;

                PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters);

                //create the DataAdapter & DataTable
                SqlDataAdapter da = new SqlDataAdapter(cmd);
                DataTable dt = new DataTable();

                //fill the DataTable using default values for DataTable names, etc.
                da.Fill(dt);

                // detach the SqlParameters from the command object, so they can be used again.
                cmd.Parameters.Clear();

                return dt;
            }
            catch (Exception ex)
            {
                Utils.WriteLogFile("执行" + commandText + "时" + ex.Message.ToString(), "异常日志");
            }
            finally
            {
                connection.Close();
            }
            return null;
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the provided SqlTransaction.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  DataTable dt = ExecuteDataTable(trans, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="transaction">a valid SqlTransaction</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>a DataTable containing the resultset generated by the command</returns>
        public static DataTable ExecuteDataTable(SqlTransaction transaction, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteDataTable(transaction, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset) against the specified SqlTransaction
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  DataTable dt = ExecuteDataTable(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("?prodid", 24));
        /// </remarks>
        /// <param name="transaction">a valid SqlTransaction</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>a DataTable containing the resultset generated by the command</returns>
        public static DataTable ExecuteDataTable(SqlTransaction transaction, CommandType commandType, string commandText,
                                                 params SqlParameter[] commandParameters)
        {
            try
            {
                //create a command and prepare it for execution
                SqlCommand cmd = new SqlCommand();
                cmd.CommandTimeout = 140;
                PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters);

                //create the DataAdapter & DataTable
                SqlDataAdapter da = new SqlDataAdapter(cmd);
                DataTable dt = new DataTable();

                //fill the DataTable using default values for DataTable names, etc.
                da.Fill(dt);

                // detach the SqlParameters from the command object, so they can be used again.
                cmd.Parameters.Clear();

                //return the DataTable
                return dt;
            }
            catch (Exception ex)
            {
                transaction.Connection.Close();
                Utils.WriteLogFile("执行" + commandText + "时" + ex.Message.ToString(), "异常日志");
            }
            return null;
        }

        #endregion ExecuteDataTable

        #region ExecuteReader

        /// <summary>
        /// this enum is used to indicate whether the connection was provided by the caller, or created by SqlHelper, so that
        /// we can set the appropriate CommandBehavior when calling ExecuteReader()
        /// </summary>
        private enum SqlConnectionOwnership
        {
            /// <summary>Connection is owned and managed by SqlHelper</summary>
            Internal,

            /// <summary>Connection is owned and managed by the caller</summary>
            External
        }

        /// <summary>
        /// Create and prepare a SqlCommand, and call ExecuteReader with the appropriate CommandBehavior.
        /// </summary>
        /// <remarks>
        /// If we created and opened the connection, we want the connection to be closed when the DataReader is closed.
        ///
        /// If the caller provided the connection, we want to leave it to them to manage.
        /// </remarks>
        /// <param name="connection">a valid SqlConnection, on which to execute this command</param>
        /// <param name="transaction">a valid SqlTransaction, or 'null'</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParameters to be associated with the command or 'null' if no parameters are required</param>
        /// <param name="connectionOwnership">indicates whether the connection parameter was provided by the caller, or created by SqlHelper</param>
        /// <returns>SqlDataReader containing the results of the command</returns>
        private static SqlDataReader ExecuteReader(SqlConnection connection, SqlTransaction transaction,
                                                   CommandType commandType, string commandText,
                                                   SqlParameter[] commandParameters,
                                                   SqlConnectionOwnership connectionOwnership)
        {
            try
            {
                //create a command and prepare it for execution
                SqlCommand cmd = new SqlCommand();
                PrepareCommand(cmd, connection, transaction, commandType, commandText, commandParameters);

                //create a reader
                SqlDataReader dr;

                // call ExecuteReader with the appropriate CommandBehavior
                if (connectionOwnership == SqlConnectionOwnership.External)
                {
                    dr = cmd.ExecuteReader();
                }
                else
                {
                    dr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
                }

                // detach the SqlParameters from the command object, so they can be used again.
                cmd.Parameters.Clear();

                return dr;
            }
            catch (Exception ex)
            {
                connection.Close();
                Utils.WriteLogFile("执行" + commandText + "时" + ex.Message.ToString(), "异常日志");
            }
            return null;
        }

        public static SqlDataReader ExecuteReader(CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteReader(connectionString, commandType, commandText, (SqlParameter[])null);
        }

        public static SqlDataReader ExecuteReader(CommandType commandType, string commandText,
                                                  params SqlParameter[] commandParameters)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteReader(connectionString, commandType, commandText, commandParameters);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the database specified in
        /// the connection string.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  SqlDataReader dr = ExecuteReader(connString, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>a SqlDataReader containing the resultset generated by the command</returns>
        public static SqlDataReader ExecuteReader(string connectionString, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteReader(connectionString, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset) against the database specified in the connection string
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  SqlDataReader dr = ExecuteReader(connString, CommandType.StoredProcedure, "GetOrders", new SqlParameter("?prodid", 24));
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>a SqlDataReader containing the resultset generated by the command</returns>
        public static SqlDataReader ExecuteReader(string connectionString, CommandType commandType, string commandText,
                                                  params SqlParameter[] commandParameters)
        {
            //create & open a SqlConnection
            SqlConnection cn = new SqlConnection(connectionString);
            cn.Open();

            try
            {
                //call the private overload that takes an internally owned connection in place of the connection string
                return ExecuteReader(cn, null, commandType, commandText, commandParameters,
                                     SqlConnectionOwnership.Internal);
            }
            catch
            {
                //if we fail to return the SqlDatReader, we need to close the connection ourselves
                cn.Close();
                throw;
            }
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the provided SqlConnection.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  SqlDataReader dr = ExecuteReader(conn, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="connection">a valid SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>a SqlDataReader containing the resultset generated by the command</returns>
        public static SqlDataReader ExecuteReader(SqlConnection connection, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteReader(connection, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset) against the specified SqlConnection
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  SqlDataReader dr = ExecuteReader(conn, CommandType.StoredProcedure, "GetOrders", new SqlParameter("?prodid", 24));
        /// </remarks>
        /// <param name="connection">a valid SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>a SqlDataReader containing the resultset generated by the command</returns>
        public static SqlDataReader ExecuteReader(SqlConnection connection, CommandType commandType, string commandText,
                                                  params SqlParameter[] commandParameters)
        {
            //pass through the call to the private overload using a null transaction value and an externally owned connection
            return ExecuteReader(connection, (SqlTransaction)null, commandType, commandText, commandParameters,
                                 SqlConnectionOwnership.External);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the provided SqlTransaction.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  SqlDataReader dr = ExecuteReader(trans, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="transaction">a valid SqlTransaction</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>a SqlDataReader containing the resultset generated by the command</returns>
        public static SqlDataReader ExecuteReader(SqlTransaction transaction, CommandType commandType,
                                                  string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteReader(transaction, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset) against the specified SqlTransaction
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///   SqlDataReader dr = ExecuteReader(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("?prodid", 24));
        /// </remarks>
        /// <param name="transaction">a valid SqlTransaction</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>a SqlDataReader containing the resultset generated by the command</returns>
        public static SqlDataReader ExecuteReader(SqlTransaction transaction, CommandType commandType,
                                                  string commandText, params SqlParameter[] commandParameters)
        {
            //pass through to private overload, indicating that the connection is owned by the caller
            return ExecuteReader(transaction.Connection, transaction, commandType, commandText, commandParameters,
                                 SqlConnectionOwnership.External);
        }

        #endregion ExecuteReader

        #region ExecuteScalar

        /// <summary>
        /// Execute a SqlCommand (that returns a 1x1 resultset and takes no parameters) against the database specified in
        /// the connection string.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  int orderCount = (int)ExecuteScalar(connString, CommandType.StoredProcedure, "GetOrderCount");
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
        public static object ExecuteScalar(string connectionString, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteScalar(connectionString, commandType, commandText, (SqlParameter[])null);
        }

        public static object ExecuteScalar(CommandType commandType, string commandText,
                                           params SqlParameter[] commandParameters)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteScalar(connectionString, commandType, commandText, commandParameters);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a 1x1 resultset) against the database specified in the connection string
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  int orderCount = (int)ExecuteScalar(connString, CommandType.StoredProcedure, "GetOrderCount", new SqlParameter("?prodid", 24));
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
        public static object ExecuteScalar(string connectionString, CommandType commandType, string commandText,
                                           params SqlParameter[] commandParameters)
        {
            //create & open a SqlConnection, and dispose of it after we are done.
            using (SqlConnection cn = new SqlConnection(connectionString))
            {
                cn.Open();

                //call the overload that takes a connection in place of the connection string
                return ExecuteScalar(cn, commandType, commandText, commandParameters);
            }
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a 1x1 resultset and takes no parameters) against the provided SqlConnection.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  int orderCount = (int)ExecuteScalar(conn, CommandType.StoredProcedure, "GetOrderCount");
        /// </remarks>
        /// <param name="connection">a valid SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
        public static object ExecuteScalar(SqlConnection connection, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteScalar(connection, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a 1x1 resultset) against the specified SqlConnection
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  int orderCount = (int)ExecuteScalar(conn, CommandType.StoredProcedure, "GetOrderCount", new SqlParameter("?prodid", 24));
        /// </remarks>
        /// <param name="connection">a valid SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
        public static object ExecuteScalar(SqlConnection connection, CommandType commandType, string commandText,
                                           params SqlParameter[] commandParameters)
        {
            try
            {
                //create a command and prepare it for execution
                SqlCommand cmd = new SqlCommand();
                PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters);

                //execute the command & return the results
                object retval = cmd.ExecuteScalar();

                // detach the SqlParameters from the command object, so they can be used again.
                cmd.Parameters.Clear();
                return retval;
            }
            catch (Exception ex)
            {
                Utils.WriteLogFile("执行" + commandText + "时" + ex.Message.ToString(), "异常日志");
            }
            finally
            {
                connection.Close();
            }
            return null;
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a 1x1 resultset and takes no parameters) against the provided SqlTransaction.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  int orderCount = (int)ExecuteScalar(trans, CommandType.StoredProcedure, "GetOrderCount");
        /// </remarks>
        /// <param name="transaction">a valid SqlTransaction</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
        public static object ExecuteScalar(SqlTransaction transaction, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteScalar(transaction, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a 1x1 resultset) against the specified SqlTransaction
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  int orderCount = (int)ExecuteScalar(trans, CommandType.StoredProcedure, "GetOrderCount", new SqlParameter("?prodid", 24));
        /// </remarks>
        /// <param name="transaction">a valid SqlTransaction</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
        public static object ExecuteScalar(SqlTransaction transaction, CommandType commandType, string commandText,
                                           params SqlParameter[] commandParameters)
        {
            try
            {
                //create a command and prepare it for execution
                SqlCommand cmd = new SqlCommand();
                PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters);

                //execute the command & return the results
                object retval = cmd.ExecuteScalar();

                // detach the SqlParameters from the command object, so they can be used again.
                cmd.Parameters.Clear();
                return retval;
            }
            catch (Exception ex)
            {
                transaction.Connection.Close();
                Utils.WriteLogFile("执行" + commandText + "时" + ex.Message.ToString(), "异常日志");
            }
            return null;
        }

        #endregion ExecuteScalar

    }