public class SQLiteHelper    {        public const string sConn = "Data Source=" + @"path";        /// 
        /// 查询，返回object ,得到查询结果的首行首列的值，若没有首行首列返回NUll        /// 
        /// 查询语句        /// 可选参数        /// 
             public static object ExecuteScalar(string sql, params SQLiteParameter[] parameters)        {            return ExecuteScalar(sql, CommandType.Text, parameters);        }        /// 
        /// 查询，返回object  ，执行SQl语句，得到查询结果的首行首列，若没有首行首列返回null         /// 
        /// 查询语句        /// 如何解释命令字符串        /// 可选的参数        /// 
             public static object ExecuteScalar(string sql, CommandType type, params SQLiteParameter[] parameters)        {            using (SQLiteConnection conn = new SQLiteConnection(sConn))            {                conn.Open();                SQLiteCommand cmd = new SQLiteCommand(sql, conn);                cmd.CommandType = type;                cmd.Parameters.AddRange(parameters);                object obj = cmd.ExecuteScalar();                cmd.Parameters.Clear();                return obj;            }        }      /// 
      /// 执行增、删、改      /// 
      /// sql语句      /// 可选参数      /// 
     
      返回int 得到受影响的行数
             public static int ExecuteNonQuery(string sql, params SQLiteParameter[] parameters)        {            return ExecuteNonQuery(sql, CommandType.Text, parameters);        }        /// 
        /// 执行增、删、改        /// 
        /// sql语句        /// 如何解释命令字符串        /// 可选参数        /// 
             public static int ExecuteNonQuery(string sql, CommandType type, params SQLiteParameter[] parameters)        {            using (SQLiteConnection conn = new SQLiteConnection(sConn))            {                conn.Open();                SQLiteCommand cmd = new SQLiteCommand(sql, conn);                cmd.CommandType = type;                cmd.Parameters.AddRange(parameters);                int num = cmd.ExecuteNonQuery();                cmd.Parameters.Clear();                return num;            }        }        /// 
        /// 断开式查询，查询多个列        /// 
        /// sql语句        /// 可选参数        /// 
     
      返回DataTable类型
             public static DataTable ExecuteTable(string sql, params SQLiteParameter[] parameters)        {            return ExecuteTable(sql, CommandType.Text, parameters);        }        /// 
        /// 断开式查询，查询结果可为多个列        /// 
        /// sql语句        /// 如何解释命令字符串        /// 可选参数        /// 
             public static DataTable ExecuteTable(string sql, CommandType type, params SQLiteParameter[] parameters)        {            SQLiteConnection conn = new SQLiteConnection(sConn);            conn.Open();            SQLiteCommand cmd = new SQLiteCommand(sql, conn);            cmd.CommandType = type;            cmd.Parameters.AddRange(parameters);            SQLiteDataAdapter sda = new SQLiteDataAdapter(cmd);            DataSet ds = new DataSet();            sda.Fill(ds);            conn.Close();            DataTable dt = ds.Tables[0];            return dt;        }    }