using System;
using System.Collections;
using System.Collections.Specialized;
using System.Data;
using System.Data.SQLite;
using System.Configuration;


    public class SQLiteHelper
    {
        //数据库连接字符串 
        // public static string connectionString = ConfigurationManager.ConnectionStrings["ProcessDB"].ConnectionString;
        public static string connectionString = "Data Source =D:\\huarui\\database\\ProcessDB.db;BinaryGUID=False;";
        public SQLiteHelper() { }

        #region 公用方法

        public static int GetMaxID(string FieldName, string TableName)
        {
            string strsql = "select max(" + FieldName + ")+1 from " + TableName;
            object obj = GetSingle(strsql);
            if (obj == null)
            {
                return 1;
            }
            else
            {
                return int.Parse(obj.ToString());
            }
        }

        public static bool Exists(string strSql)
        {
            object obj = GetSingle(strSql);
            int cmdresult;
            if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
            {
                cmdresult = 0;
            }
            else
            {
                cmdresult = int.Parse(obj.ToString());
            }
            if (cmdresult == 0)
            {
                return false;
            }
            else
            {
                return true;
            }
        }

        public static bool Exists(string strSql, params SQLiteParameter[] cmdParms)
        {
            object obj = GetSingle(strSql, cmdParms);
            int cmdresult;
            if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
            {
                cmdresult = 0;
            }
            else
            {
                cmdresult = int.Parse(obj.ToString());
            }
            if (cmdresult == 0)
            {
                return false;
            }
            else
            {
                return true;
            }
        }

        #endregion

        #region 执行简单SQL语句

        /// <summary>
        /// 执行SQL语句，返回影响的记录数
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <returns>影响的记录数</returns>
        public static int ExecuteSql(string SQLString)
        {
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                using (SQLiteCommand cmd = new SQLiteCommand(SQLString, connection))
                {
                    try
                    {
                        connection.Open();
                        int rows = cmd.ExecuteNonQuery();
                        return rows;
                    }
                    catch (System.Data.SQLite.SQLiteException E)
                    {
                        connection.Close();
                        throw new Exception(E.Message);
                    }
                }
            }
        }

        /// <summary>
        /// 执行SQL语句，设置命令的执行等待时间
        /// </summary>
        /// <param name="SQLString"></param>
        /// <param name="Times"></param>
        /// <returns></returns>
        public static int ExecuteSqlByTime(string SQLString, int Times)
        {
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                using (SQLiteCommand cmd = new SQLiteCommand(SQLString, connection))
                {
                    try
                    {
                        connection.Open();
                        cmd.CommandTimeout = Times;
                        int rows = cmd.ExecuteNonQuery();
                        return rows;
                    }
                    catch (System.Data.SQLite.SQLiteException E)
                    {
                        connection.Close();
                        throw new Exception(E.Message);
                    }
                }
            }
        }

        /// <summary>
        /// 执行多条SQL语句，实现数据库事务。
        /// </summary>
        /// <param name="SQLStringList">多条SQL语句</param> 
        public static bool ExecuteSqlTran(ArrayList SQLStringList)
        {
            bool isSuccess = false;
            using (SQLiteConnection conn = new SQLiteConnection(connectionString))
            {
                conn.Open();
                SQLiteCommand cmd = new SQLiteCommand();
                cmd.Connection = conn;
                cmd.CommandText = "PRAGMA synchronous = OFF;";
                cmd.ExecuteNonQuery();
                SQLiteTransaction tx = conn.BeginTransaction();
                cmd.Transaction = tx;
                try
                {
                    for (int n = 0; n < SQLStringList.Count; n++)
                    {
                        string strsql = SQLStringList[n].ToString();
                        if (strsql.Trim().Length > 1)
                        {
                            cmd.CommandText = strsql;
                            cmd.ExecuteNonQuery();
                        }
                    }
                    tx.Commit();
                    isSuccess = true;
                }
                catch (System.Data.SQLite.SQLiteException E)
                {
                    tx.Rollback();
                    isSuccess = false;
                    throw new Exception(E.Message);
                }
            }
            return isSuccess;
        }

        /// <summary>
        /// 执行带一个存储过程参数的的SQL语句。
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <param name="content">参数内容,比如一个字段是格式复杂的文章，有特殊符号，可以通过这个方式添加</param>
        /// <returns>影响的记录数</returns>
        public static int ExecuteSql(string SQLString, string content)
        {
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                SQLiteCommand cmd = new SQLiteCommand(SQLString, connection);
                SQLiteParameter myParameter = new SQLiteParameter("@content", DbType.String);
                myParameter.Value = content;
                cmd.Parameters.Add(myParameter);
                try
                {
                    connection.Open();
                    int rows = cmd.ExecuteNonQuery();
                    return rows;
                }
                catch (System.Data.SQLite.SQLiteException E)
                {
                    throw new Exception(E.Message);
                }
                finally
                {
                    cmd.Dispose();
                    connection.Close();
                }
            }
        }

        /// <summary>
        /// 执行带一个存储过程参数的的SQL语句。
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <param name="content">参数内容,比如一个字段是格式复杂的文章，有特殊符号，可以通过这个方式添加</param>
        /// <returns>影响的记录数</returns>
        public static object ExecuteSqlGet(string SQLString, string content)
        {
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                SQLiteCommand cmd = new SQLiteCommand(SQLString, connection);
                SQLiteParameter myParameter = new SQLiteParameter("@content", DbType.String);
                myParameter.Value = content;
                cmd.Parameters.Add(myParameter);
                try
                {
                    connection.Open();
                    object obj = cmd.ExecuteScalar();
                    if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                    {
                        return null;
                    }
                    else
                    {
                        return obj;
                    }
                }
                catch (System.Data.SQLite.SQLiteException E)
                {
                    throw new Exception(E.Message);
                }
                finally
                {
                    cmd.Dispose();
                    connection.Close();
                }
            }
        }

        /// <summary>
        /// 向数据库里插入图像格式的字段(和上面情况类似的另一种实例)
        /// </summary>
        /// <param name="strSQL">SQL语句</param>
        /// <param name="fs">图像字节,数据库的字段类型为image的情况</param>
        /// <returns>影响的记录数</returns>
        public static int ExecuteSqlInsertImg(string strSQL, byte[] fs)
        {
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                SQLiteCommand cmd = new SQLiteCommand(strSQL, connection);
                SQLiteParameter myParameter = new SQLiteParameter("@fs", DbType.Binary);
                myParameter.Value = fs;
                cmd.Parameters.Add(myParameter);
                try
                {
                    connection.Open();
                    int rows = cmd.ExecuteNonQuery();
                    return rows;
                }
                catch (System.Data.SQLite.SQLiteException E)
                {
                    throw new Exception(E.Message);
                }
                finally
                {
                    cmd.Dispose();
                    connection.Close();
                }
            }
        }

        /// <summary>
        /// 执行一条计算查询结果语句，返回查询结果（object）。
        /// </summary>
        /// <param name="SQLString">计算查询结果语句</param>
        /// <returns>查询结果（object）</returns>
        public static object GetSingle(string SQLString)
        {
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                using (SQLiteCommand cmd = new SQLiteCommand(SQLString, connection))
                {
                    try
                    {
                        connection.Open();
                        object obj = cmd.ExecuteScalar();
                        if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                        {
                            return null;
                        }
                        else
                        {
                            return obj;
                        }
                    }
                    catch (System.Data.SQLite.SQLiteException e)
                    {
                        connection.Close();
                        throw new Exception(e.Message);
                    }
                }
            }
        }

        /// <summary>
        /// 执行查询语句，返回SQLiteDataReader(使用该方法切记要手工关闭SQLiteDataReader和连接)
        /// </summary>
        /// <param name="strSQL">查询语句</param>
        /// <returns>SQLiteDataReader</returns>
        public static SQLiteDataReader ExecuteReader(string strSQL)
        {
            SQLiteConnection connection = new SQLiteConnection(connectionString);
            SQLiteCommand cmd = new SQLiteCommand(strSQL, connection);
            try
            {
                connection.Open();
                SQLiteDataReader myReader = cmd.ExecuteReader();
                return myReader;
            }
            catch (System.Data.SQLite.SQLiteException e)
            {
                throw new Exception(e.Message);
            }
            //finally //不能在此关闭，否则，返回的对象将无法使用
            //{
            //    cmd.Dispose();
            //    connection.Close();
            //}
        }

        /// <summary>
        /// 执行查询语句，返回DataSet
        /// </summary>
        /// <param name="SQLString">查询语句</param>
        /// <returns>DataSet</returns>
        public static DataSet Query(string SQLString)
        {
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                DataSet ds = new DataSet();
                try
                {
                    connection.Open();
                    SQLiteDataAdapter command = new SQLiteDataAdapter(SQLString, connection);
                    command.Fill(ds, "ds");
                    connection.Close();
                    command.Dispose();
                }
                catch (System.Data.SQLite.SQLiteException ex)
                {
                    throw new Exception(ex.Message);
                }
                return ds;
            }
        }

        public static DataSet Query(string SQLString, string TableName)
        {
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                DataSet ds = new DataSet();
                try
                {
                    connection.Open();
                    SQLiteDataAdapter command = new SQLiteDataAdapter(SQLString, connection);
                    command.Fill(ds, TableName);
                }
                catch (System.Data.SQLite.SQLiteException ex)
                {
                    throw new Exception(ex.Message);
                }
                return ds;
            }
        }

        /// <summary>
        /// 执行查询语句，返回DataSet,设置命令的执行等待时间
        /// </summary>
        /// <param name="SQLString"></param>
        /// <param name="Times"></param>
        /// <returns></returns>
        public static DataSet Query(string SQLString, int Times)
        {
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                DataSet ds = new DataSet();
                try
                {
                    connection.Open();
                    SQLiteDataAdapter command = new SQLiteDataAdapter(SQLString, connection);
                    command.SelectCommand.CommandTimeout = Times;
                    command.Fill(ds, "ds");
                }
                catch (System.Data.SQLite.SQLiteException ex)
                {
                    throw new Exception(ex.Message);
                }
                return ds;
            }
        }

        #endregion

        #region 执行带参数的SQL语句

        /// <summary>
        /// 执行SQL语句，返回影响的记录数
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <returns>影响的记录数</returns>
        public static int ExecuteSql(string SQLString, params SQLiteParameter[] cmdParms)
        {
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                using (SQLiteCommand cmd = new SQLiteCommand())
                {
                    try
                    {
                        PrepareCommand(cmd, connection, null, SQLString, cmdParms);
                        int rows = cmd.ExecuteNonQuery();
                        cmd.Parameters.Clear();
                        return rows;
                    }
                    catch (System.Data.SQLite.SQLiteException E)
                    {
                        throw new Exception(E.Message);
                    }
                }
            }
        }

        /// <summary>
        /// 执行多条SQL语句，实现数据库事务。
        /// </summary>
        /// <param name="SQLStringList">SQL语句的哈希表（key为sql语句，value是该语句的SQLiteParameter[]）</param>
        public static void ExecuteSqlTran(Hashtable SQLStringList)
        {
            using (SQLiteConnection conn = new SQLiteConnection(connectionString))
            {
                conn.Open();
                using (SQLiteTransaction trans = conn.BeginTransaction())
                {
                    SQLiteCommand cmd = new SQLiteCommand();
                    try
                    {
                        //循环
                        foreach (DictionaryEntry myDE in SQLStringList)
                        {
                            string cmdText = myDE.Key.ToString();
                            SQLiteParameter[] cmdParms = (SQLiteParameter[])myDE.Value;
                            PrepareCommand(cmd, conn, trans, cmdText, cmdParms);
                            int val = cmd.ExecuteNonQuery();
                            cmd.Parameters.Clear();
                        }
                        trans.Commit();
                    }
                    catch (System.Data.SQLite.SQLiteException e)
                    {
                        trans.Rollback();
                        throw new Exception(e.Message);
                    }
                }
            }
        }

        /// <summary>
        /// 执行一条计算查询结果语句，返回查询结果（object）。
        /// </summary>
        /// <param name="SQLString">计算查询结果语句</param>
        /// <returns>查询结果（object）</returns>
        public static object GetSingle(string SQLString, params SQLiteParameter[] cmdParms)
        {
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                using (SQLiteCommand cmd = new SQLiteCommand())
                {
                    try
                    {
                        PrepareCommand(cmd, connection, null, SQLString, cmdParms);
                        object obj = cmd.ExecuteScalar();
                        cmd.Parameters.Clear();
                        if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                        {
                            return null;
                        }
                        else
                        {
                            return obj;
                        }
                    }
                    catch (System.Data.SQLite.SQLiteException e)
                    {
                        throw new Exception(e.Message);
                    }
                }
            }
        }

        /// <summary>
        /// 执行查询语句，返回SQLiteDataReader (使用该方法切记要手工关闭SQLiteDataReader和连接)
        /// </summary>
        /// <param name="strSQL">查询语句</param>
        /// <returns>SQLiteDataReader</returns>
        public static SQLiteDataReader ExecuteReader(string SQLString, params SQLiteParameter[] cmdParms)
        {
            SQLiteConnection connection = new SQLiteConnection(connectionString);
            SQLiteCommand cmd = new SQLiteCommand();
            try
            {
                PrepareCommand(cmd, connection, null, SQLString, cmdParms);
                SQLiteDataReader myReader = cmd.ExecuteReader();
                cmd.Parameters.Clear();
                return myReader;
            }
            catch (System.Data.SQLite.SQLiteException e)
            {
                throw new Exception(e.Message);
            }
            //finally //不能在此关闭，否则，返回的对象将无法使用
            //{
            // cmd.Dispose();
            // connection.Close();
            //} 

        }

        /// <summary>
        /// 执行查询语句，返回DataSet
        /// </summary>
        /// <param name="SQLString">查询语句</param>
        /// <returns>DataSet</returns>
        public static DataSet Query(string SQLString, params SQLiteParameter[] cmdParms)
        {
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                SQLiteCommand cmd = new SQLiteCommand();
                PrepareCommand(cmd, connection, null, SQLString, cmdParms);
                using (SQLiteDataAdapter da = new SQLiteDataAdapter(cmd))
                {
                    DataSet ds = new DataSet();
                    try
                    {
                        da.Fill(ds, "ds");
                        cmd.Parameters.Clear();
                    }
                    catch (System.Data.SQLite.SQLiteException ex)
                    {
                        throw new Exception(ex.Message);
                    }
                    return ds;
                }
            }
        }

        public static void PrepareCommand(SQLiteCommand cmd, SQLiteConnection conn,
        SQLiteTransaction trans, string cmdText, SQLiteParameter[] cmdParms)
        {
            if (conn.State != ConnectionState.Open)
                conn.Open();
            cmd.Connection = conn;
            cmd.CommandText = cmdText;
            if (trans != null)
                cmd.Transaction = trans;
            cmd.CommandType = CommandType.Text;//cmdType;
            if (cmdParms != null)
            {
                foreach (SQLiteParameter parameter in cmdParms)
                {
                    if ((parameter.Direction == ParameterDirection.InputOutput
                    || parameter.Direction == ParameterDirection.Input) &&
                    (parameter.Value == null))
                    {
                        parameter.Value = DBNull.Value;
                    }
                    cmd.Parameters.Add(parameter);
                }
            }
        }

        #endregion

        #region 参数转换
        /// <summary>
        /// 放回一个SQLiteParameter
        /// </summary>
        /// <param name="name">参数名字</param>
        /// <param name="type">参数类型</param>
        /// <param name="size">参数大小</param>
        /// <param name="value">参数值</param>
        /// <returns>SQLiteParameter的值</returns>
        public static SQLiteParameter MakeSQLiteParameter(string name,
        DbType type, int size, object value)
        {
            SQLiteParameter parm = new SQLiteParameter(name, type, size);
            parm.Value = value;
            return parm;
        }

        public static SQLiteParameter MakeSQLiteParameter(string name, DbType type, object value)
        {
            SQLiteParameter parm = new SQLiteParameter(name, type);
            parm.Value = value;
            return parm;
        }

        #endregion
    }