using System;using System.Data;using System.Text.RegularExpressions;using System.Xml;using System.IO;using System.Collections;using System.Data.SQLite;namespace DBUtility.SQLite{    ///     /// SQLiteHelper is a utility class similar to "SQLHelper" in MS    /// Data Access Application Block and follows similar pattern.    ///     public class SQLiteHelper    {        ///         /// Creates a new  instance. The ctor is marked private since all members are static.        ///         private SQLiteHelper()        {        }        ///         /// Creates the command.        ///         /// Connection.        /// Command text.        /// Command parameters.        /// SQLite Command        public static SQLiteCommand CreateCommand(SQLiteConnection connection, string commandText, params SQLiteParameter[] commandParameters)        {            SQLiteCommand cmd = new SQLiteCommand(commandText, connection);            if (commandParameters.Length > 0)            {                foreach (SQLiteParameter parm in commandParameters)                    cmd.Parameters.Add(parm);            }            return cmd;        }        ///         /// Creates the command.        ///         /// Connection string.        /// Command text.        /// Command parameters.        /// SQLite Command        public static SQLiteCommand CreateCommand(string connectionString, string commandText, params SQLiteParameter[] commandParameters)        {            SQLiteConnection cn = new SQLiteConnection(connectionString);            SQLiteCommand cmd = new SQLiteCommand(commandText, cn);            if (commandParameters.Length > 0)            {                foreach (SQLiteParameter parm in commandParameters)                    cmd.Parameters.Add(parm);            }            return cmd;        }        ///         /// Creates the parameter.        ///         /// Name of the parameter.        /// Parameter type.        /// Parameter value.        /// SQLiteParameter        public static SQLiteParameter CreateParameter(string parameterName, System.Data.DbType parameterType, object parameterValue)        {            SQLiteParameter parameter = new SQLiteParameter();            parameter.DbType = parameterType;            parameter.ParameterName = parameterName;            parameter.Value = parameterValue;            return parameter;        }        ///         /// Shortcut method to execute dataset from SQL Statement and object[] arrray of parameter values        ///         /// SQLite Connection string        /// SQL Statement with embedded "@param" style parameter names        /// object[] array of parameter values        ///         public static DataSet ExecuteDataSet(string connectionString, string commandText, object[] paramList)        {            SQLiteConnection cn = new SQLiteConnection(connectionString);            SQLiteCommand cmd = cn.CreateCommand();            cmd.CommandText = commandText;            if (paramList != null)            {                AttachParameters(cmd,commandText, paramList);            }            DataSet ds = new DataSet();            if (cn.State == ConnectionState.Closed)                cn.Open();            SQLiteDataAdapter da = new SQLiteDataAdapter(cmd);            da.Fill(ds);            da.Dispose();            cmd.Dispose();            cn.Close();            return ds;        }        ///         /// Shortcut method to execute dataset from SQL Statement and object[] arrray of  parameter values        ///         /// Connection.        /// Command text.        /// Param list.        ///         public static DataSet ExecuteDataSet(SQLiteConnection cn, string commandText, object[] paramList)        {            SQLiteCommand cmd = cn.CreateCommand();            cmd.CommandText = commandText;            if (paramList != null)            {                AttachParameters(cmd,commandText, paramList);            }            DataSet ds = new DataSet();            if (cn.State == ConnectionState.Closed)                cn.Open();            SQLiteDataAdapter da = new SQLiteDataAdapter(cmd);            da.Fill(ds);            da.Dispose();            cmd.Dispose();            cn.Close();            return ds;        }        ///         /// Executes the dataset from a populated Command object.        ///         /// Fully populated SQLiteCommand        /// DataSet        public static DataSet ExecuteDataset(SQLiteCommand cmd)        {            if (cmd.Connection.State == ConnectionState.Closed)                cmd.Connection.Open();            DataSet ds = new DataSet();            SQLiteDataAdapter da = new SQLiteDataAdapter(cmd);            da.Fill(ds);            da.Dispose();            cmd.Connection.Close();            cmd.Dispose();            return ds;        }        ///         /// Executes the dataset in a SQLite Transaction        ///         /// SQLiteTransaction. Transaction consists of Connection, Transaction,  /// and Command, all of which must be created prior to making this method call.         /// Command text.        /// Sqlite Command parameters.        /// DataSet        /// user must examine Transaction Object and handle transaction.connection .Close, etc.        public static DataSet ExecuteDataset(SQLiteTransaction transaction, string commandText, params SQLiteParameter[] commandParameters)        {            if (transaction == null) throw new ArgumentNullException("transaction");            if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rolled back or committed, please provide an open transaction.", "transaction");            IDbCommand cmd = transaction.Connection.CreateCommand();            cmd.CommandText = commandText;            foreach (SQLiteParameter parm in commandParameters)            {                cmd.Parameters.Add(parm);            }            if (transaction.Connection.State == ConnectionState.Closed)                transaction.Connection.Open();            DataSet ds = ExecuteDataset((SQLiteCommand)cmd);            return ds;        }        ///         /// Executes the dataset with Transaction and object array of parameter values.        ///         /// SQLiteTransaction. Transaction consists of Connection, Transaction,    /// and Command, all of which must be created prior to making this method call.         /// Command text.        /// object[] array of parameter values.        /// DataSet        /// user must examine Transaction Object and handle transaction.connection .Close, etc.        public static DataSet ExecuteDataset(SQLiteTransaction transaction, string commandText, object[] commandParameters)        {            if (transaction == null) throw new ArgumentNullException("transaction");            if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rolled back or committed,                                                          please provide an open transaction.", "transaction");            IDbCommand cmd = transaction.Connection.CreateCommand();            cmd.CommandText = commandText;            AttachParameters((SQLiteCommand)cmd,cmd.CommandText, commandParameters);            if (transaction.Connection.State == ConnectionState.Closed)                transaction.Connection.Open();            DataSet ds = ExecuteDataset((SQLiteCommand)cmd);            return ds;        }        #region UpdateDataset        ///         /// Executes the respective command for each inserted, updated, or deleted row in the DataSet.        ///         ///         /// e.g.:          ///  UpdateDataset(conn, insertCommand, deleteCommand, updateCommand, dataSet, "Order");        ///         /// A valid SQL statement  to insert new records into the data source        /// A valid SQL statement to delete records from the data source        /// A valid SQL statement used to update records in the data source        /// The DataSet used to update the data source        /// The DataTable used to update the data source.        public static void UpdateDataset(SQLiteCommand insertCommand, SQLiteCommand deleteCommand, SQLiteCommand updateCommand, DataSet dataSet, string tableName)        {            if (insertCommand == null) throw new ArgumentNullException("insertCommand");            if (deleteCommand == null) throw new ArgumentNullException("deleteCommand");            if (updateCommand == null) throw new ArgumentNullException("updateCommand");            if (tableName == null || tableName.Length == 0) throw new ArgumentNullException("tableName");            // Create a SQLiteDataAdapter, and dispose of it after we are done            using (SQLiteDataAdapter dataAdapter = new SQLiteDataAdapter())            {                // Set the data adapter commands                dataAdapter.UpdateCommand = updateCommand;                dataAdapter.InsertCommand = insertCommand;                dataAdapter.DeleteCommand = deleteCommand;                // Update the dataset changes in the data source                dataAdapter.Update(dataSet, tableName);                // Commit all the changes made to the DataSet                dataSet.AcceptChanges();            }        }        #endregion        ///         /// ShortCut method to return IDataReader        /// NOTE: You should explicitly close the Command.connection you passed in as        /// well as call Dispose on the Command  after reader is closed.        /// We do this because IDataReader has no underlying Connection Property.        ///         /// SQLiteCommand Object        /// SQL Statement with optional embedded "@param" style parameters        /// object[] array of parameter values        /// IDataReader        public static IDataReader ExecuteReader(SQLiteCommand cmd, string commandText, object[] paramList)        {            if (cmd.Connection == null)                throw new ArgumentException("Command must have live connection attached.", "cmd");            cmd.CommandText = commandText;            AttachParameters(cmd,commandText, paramList);            if (cmd.Connection.State == ConnectionState.Closed)                cmd.Connection.Open();            IDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);            return rdr;        }        ///         /// Shortcut to ExecuteNonQuery with SqlStatement and object[] param values        ///         /// SQLite Connection String        /// Sql Statement with embedded "@param" style parameters        /// object[] array of parameter values        ///         public static int ExecuteNonQuery(string connectionString, string commandText, params object[] paramList)        {            SQLiteConnection cn = new SQLiteConnection(connectionString);            SQLiteCommand cmd = cn.CreateCommand();            cmd.CommandText = commandText;            AttachParameters(cmd,commandText, paramList);            if (cn.State == ConnectionState.Closed)                cn.Open();            int result = cmd.ExecuteNonQuery();            cmd.Dispose();            cn.Close();            return result;        }        public static int ExecuteNonQuery(SQLiteConnection cn, string commandText, params  object[] paramList)        {            SQLiteCommand cmd = cn.CreateCommand();            cmd.CommandText = commandText;            AttachParameters(cmd,commandText, paramList);            if (cn.State == ConnectionState.Closed)                cn.Open();            int result = cmd.ExecuteNonQuery();            cmd.Dispose();            cn.Close();            return result;        }        ///         /// Executes  non-query sql Statment with Transaction        ///         /// SQLiteTransaction. Transaction consists of Connection, Transaction,   /// and Command, all of which must be created prior to making this method call.         /// Command text.        /// Param list.        /// Integer        /// user must examine Transaction Object and handle transaction.connection .Close, etc.        public static int ExecuteNonQuery(SQLiteTransaction transaction, string commandText, params  object[] paramList)        {            if (transaction == null) throw new ArgumentNullException("transaction");            if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rolled back or committed,                                                        please provide an open transaction.", "transaction");            IDbCommand cmd = transaction.Connection.CreateCommand();            cmd.CommandText = commandText;            AttachParameters((SQLiteCommand)cmd,cmd.CommandText, paramList);            if (transaction.Connection.State == ConnectionState.Closed)                transaction.Connection.Open();            int result = cmd.ExecuteNonQuery();            cmd.Dispose();            return result;        }        ///         /// Executes the non query.        ///         /// CMD.        ///         public static int ExecuteNonQuery(IDbCommand cmd)        {            if (cmd.Connection.State == ConnectionState.Closed)                cmd.Connection.Open();            int result = cmd.ExecuteNonQuery();            cmd.Connection.Close();            cmd.Dispose();            return result;        }        ///         /// Shortcut to ExecuteScalar with Sql Statement embedded params and object[] param values        ///         /// SQLite Connection String        /// SQL statment with embedded "@param" style parameters        /// object[] array of param values        ///         public static object ExecuteScalar(string connectionString, string commandText, params  object[] paramList)        {            SQLiteConnection cn = new SQLiteConnection(connectionString);            SQLiteCommand cmd = cn.CreateCommand();            cmd.CommandText = commandText;            AttachParameters(cmd,commandText, paramList);            if (cn.State == ConnectionState.Closed)                cn.Open();            object result = cmd.ExecuteScalar();            cmd.Dispose();            cn.Close();            return result;        }        ///         /// Execute XmlReader with complete Command        ///         /// SQLite Command        /// XmlReader        public static XmlReader ExecuteXmlReader(IDbCommand command)        { // open the connection if necessary, but make sure we             // know to close it when we�re done.            if (command.Connection.State != ConnectionState.Open)            {                command.Connection.Open();            }            // get a data adapter              SQLiteDataAdapter da = new SQLiteDataAdapter((SQLiteCommand)command);            DataSet ds = new DataSet();            // fill the data set, and return the schema information            da.MissingSchemaAction = MissingSchemaAction.AddWithKey;            da.Fill(ds);            // convert our dataset to XML            StringReader stream = new StringReader(ds.GetXml());            command.Connection.Close();            // convert our stream of text to an XmlReader            return new XmlTextReader(stream);        }        ///         /// Parses parameter names from SQL Statement, assigns values from object array ,   /// and returns fully populated ParameterCollection.        ///         /// Sql Statement with "@param" style embedded parameters        /// object[] array of parameter values        /// SQLiteParameterCollection        /// Status experimental. Regex appears to be handling most issues. Note that parameter object array must be in same ///order as parameter names appear in SQL statement.        private static SQLiteParameterCollection AttachParameters(SQLiteCommand cmd, string commandText, params  object[] paramList)        {            if (paramList == null || paramList.Length == 0) return null;            SQLiteParameterCollection coll = cmd.Parameters;            string parmString = commandText.Substring(commandText.IndexOf("@"));            // pre-process the string so always at least 1 space after a comma.            parmString = parmString.Replace(",", " ,");            // get the named parameters into a match collection            string pattern = @"(@)\S*(.*?)\b";            Regex ex = new Regex(pattern, RegexOptions.IgnoreCase);            MatchCollection mc = ex.Matches(parmString);            string[] paramNames = new string[mc.Count];            int i = 0;            foreach (Match m in mc)            {                paramNames[i] = m.Value;                i++;            }            // now let's type the parameters            int j = 0;            Type t = null;            foreach (object o in paramList)            {                t = o.GetType();                SQLiteParameter parm = new SQLiteParameter();                switch (t.ToString())                {                    case ("DBNull"):                    case ("Char"):                    case ("SByte"):                    case ("UInt16"):                    case ("UInt32"):                    case ("UInt64"):                        throw new SystemException("Invalid data type");                    case ("System.String"):                        parm.DbType = DbType.String;                        parm.ParameterName = paramNames[j];                        parm.Value = (string)paramList[j];                        coll.Add(parm);                        break;                    case ("System.Byte[]"):                        parm.DbType = DbType.Binary;                        parm.ParameterName = paramNames[j];                        parm.Value = (byte[])paramList[j];                        coll.Add(parm);                        break;                    case ("System.Int32"):                        parm.DbType = DbType.Int32;                        parm.ParameterName = paramNames[j];                        parm.Value = (int)paramList[j];                        coll.Add(parm);                        break;                    case ("System.Boolean"):                        parm.DbType = DbType.Boolean;                        parm.ParameterName = paramNames[j];                        parm.Value = (bool)paramList[j];                        coll.Add(parm);                        break;                    case ("System.DateTime"):                        parm.DbType = DbType.DateTime;                        parm.ParameterName = paramNames[j];                        parm.Value = Convert.ToDateTime(paramList[j]);                        coll.Add(parm);                        break;                    case ("System.Double"):                        parm.DbType = DbType.Double;                        parm.ParameterName = paramNames[j];                        parm.Value = Convert.ToDouble(paramList[j]);                        coll.Add(parm);                        break;                    case ("System.Decimal"):                        parm.DbType = DbType.Decimal;                        parm.ParameterName = paramNames[j];                        parm.Value = Convert.ToDecimal(paramList[j]);                        break;                    case ("System.Guid"):                        parm.DbType = DbType.Guid;                        parm.ParameterName = paramNames[j];                        parm.Value = (System.Guid)(paramList[j]);                        break;                    case ("System.Object"):                        parm.DbType = DbType.Object;                        parm.ParameterName = paramNames[j];                        parm.Value = paramList[j];                        coll.Add(parm);                        break;                    default:                        throw new SystemException("Value is of unknown data type");                } // end switch                j++;            }            return coll;        }        ///         /// Executes non query typed params from a DataRow        ///         /// Command.        /// Data row.        /// Integer result code        public static int ExecuteNonQueryTypedParams(IDbCommand command, DataRow dataRow)        {            int retVal = 0;            // If the row has values, the store procedure parameters must be initialized            if (dataRow != null && dataRow.ItemArray.Length > 0)            {                // Set the parameters values                AssignParameterValues(command.Parameters, dataRow);                retVal = ExecuteNonQuery(command);            }            else            {                retVal = ExecuteNonQuery(command);            }            return retVal;        }        ///         /// This method assigns dataRow column values to an IDataParameterCollection        ///         /// The IDataParameterCollection to be assigned values        /// The dataRow used to hold the command's parameter values        /// Thrown if any of the parameter names are invalid.        protected internal static void AssignParameterValues(IDataParameterCollection commandParameters, DataRow dataRow)        {            if (commandParameters == null || dataRow == null)            {                // Do nothing if we get no data                return;            }            DataColumnCollection columns = dataRow.Table.Columns;            int i = 0;            // Set the parameters values            foreach (IDataParameter commandParameter in commandParameters)            {                // Check the parameter name                if (commandParameter.ParameterName == null ||                 commandParameter.ParameterName.Length <= 1)                    throw new InvalidOperationException(string.Format(                           "Please provide a valid parameter name on the parameter #{0},                            the ParameterName property has the following value: '{1}'.",                     i, commandParameter.ParameterName));                if (columns.Contains(commandParameter.ParameterName))                    commandParameter.Value = dataRow[commandParameter.ParameterName];                else if (columns.Contains(commandParameter.ParameterName.Substring(1)))                    commandParameter.Value = dataRow[commandParameter.ParameterName.Substring(1)];                i++;            }        }        ///         /// This method assigns dataRow column values to an array of IDataParameters        ///         /// Array of IDataParameters to be assigned values        /// The dataRow used to hold the stored procedure's parameter values        /// Thrown if any of the parameter names are invalid.        protected void AssignParameterValues(IDataParameter[] commandParameters, DataRow dataRow)        {            if ((commandParameters == null) || (dataRow == null))            {                // Do nothing if we get no data                return;            }            DataColumnCollection columns = dataRow.Table.Columns;            int i = 0;            // Set the parameters values            foreach (IDataParameter commandParameter in commandParameters)            {                // Check the parameter name                if (commandParameter.ParameterName == null ||                 commandParameter.ParameterName.Length <= 1)                    throw new InvalidOperationException(string.Format(                     "Please provide a valid parameter name on the parameter #{0}, the ParameterName property has the following value: '{1}'.",                     i, commandParameter.ParameterName));                if (columns.Contains(commandParameter.ParameterName))                    commandParameter.Value = dataRow[commandParameter.ParameterName];                else if (columns.Contains(commandParameter.ParameterName.Substring(1)))                    commandParameter.Value = dataRow[commandParameter.ParameterName.Substring(1)];                i++;            }        }        ///         /// This method assigns an array of values to an array of IDataParameters        ///         /// Array of IDataParameters to be assigned values        /// Array of objects holding the values to be assigned        /// Thrown if an incorrect number of parameters are passed.        protected void AssignParameterValues(IDataParameter[] commandParameters, params  object[] parameterValues)        {            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 IDataParameters, assigning the values from the corresponding position in the             // value array            for (int i = 0, j = commandParameters.Length, k = 0; i < j; i++)            {                if (commandParameters[i].Direction != ParameterDirection.ReturnValue)                {                    // If the current array value derives from IDataParameter, then assign its Value property                    if (parameterValues[k] is IDataParameter)                    {                        IDataParameter paramInstance;                        paramInstance = (IDataParameter)parameterValues[k];                        if (paramInstance.Direction == ParameterDirection.ReturnValue)                        {                            paramInstance = (IDataParameter)parameterValues[++k];                        }                        if (paramInstance.Value == null)                        {                            commandParameters[i].Value = DBNull.Value;                        }                        else                        {                            commandParameters[i].Value = paramInstance.Value;                        }                    }                    else if (parameterValues[k] == null)                    {                        commandParameters[i].Value = DBNull.Value;                    }                    else                    {                        commandParameters[i].Value = parameterValues[k];                    }                    k++;                }            }        }    }}using System;using System.Data.SQLite;namespace SQLiteSamples{    class Program    {        //数据库连接        SQLiteConnection m_dbConnection;        static void Main(string[] args)        {            Program p = new Program();        }        public Program()        {            createNewDatabase();            connectToDatabase();            createTable();            fillTable();            printHighscores();        }        //创建一个空的数据库        void createNewDatabase()        {            SQLiteConnection.CreateFile("MyDatabase.sqlite");        }        //创建一个连接到指定数据库        void connectToDatabase()        {            m_dbConnection = new SQLiteConnection("Data Source=MyDatabase.sqlite;Version=3;");            m_dbConnection.Open();        }        //在指定数据库中创建一个table        void createTable()        {            string sql = "create table highscores (name varchar(20), score int)";            SQLiteCommand command = new SQLiteCommand(sql, m_dbConnection);            command.ExecuteNonQuery();        }        //插入一些数据        void fillTable()        {            string sql = "insert into highscores (name, score) values ('Me', 3000)";            SQLiteCommand command = new SQLiteCommand(sql, m_dbConnection);            command.ExecuteNonQuery();            sql = "insert into highscores (name, score) values ('Myself', 6000)";            command = new SQLiteCommand(sql, m_dbConnection);            command.ExecuteNonQuery();            sql = "insert into highscores (name, score) values ('And I', 9001)";            command = new SQLiteCommand(sql, m_dbConnection);            command.ExecuteNonQuery();        }        //使用sql查询语句，并显示结果        void printHighscores()        {            string sql = "select * from highscores order by score desc";            SQLiteCommand command = new SQLiteCommand(sql, m_dbConnection);            SQLiteDataReader reader = command.ExecuteReader();            while (reader.Read())                Console.WriteLine("Name: " + reader["name"] + "\tScore: " + reader["score"]);            Console.ReadLine();        }    }}