簡單SQLite 數據庫 *** 作Demo

概述public class DbHelperSQLite { public string connectionString = "Data Source=" + AppDomain.CurrentDomain.BaseDirectory + @"WIP.db;Version=3;"; public event EventHandler<SQLiteMess

public class DbHelpersqlite    {        public string connectionString = "Data Source=" + AppDomain.CurrentDomain.BaseDirectory + @"WIP.db;Version=3;";        public event EventHandler<sqliteMessageEventArg> sqliteMessageEvent;        public DbHelpersqlite()        { }           /// <summary>        /// 執行單條sql語句，返回值(bool)        /// </summary>        /// <param name="sqlString"></param>        /// <returns></returns>        public bool Executesql(string sqlString)        {            var eventHandle = sqliteMessageEvent;            string msg = "";            using (sqliteConnection connection = new sqliteConnection(connectionString))            {                using (sqliteCommand cmd = new sqliteCommand(sqlString,connection))                {                    try                    {                        connection.open();                        cmd.ExecuteNonquery();                        msg = "sql Command: " + sqlString + " Excute Success!";                        if (eventHandle != null)                        {                            eventHandle(null,new sqliteMessageEventArg(sqliteMessageType.Msg,msg,sqlString));                        }                        return true;                    }                    catch (sqliteException ex)                    {                        msg = "Execute sql Error Message: " + ex.Message;                        if (eventHandle != null)                        {                            eventHandle(null,new sqliteMessageEventArg(sqliteMessageType.Errorsql,sqlString));                        }                        return false;                    }                    finally                    {                        connection.Close();                        cmd.dispose();                    }                }            }        }        /// <summary>        /// 獲取最大值，返回值(int)        /// </summary>        /// <param name="FIEldname">欄位名稱</param>        /// <param name="tablename">表名稱</param>        /// <returns></returns>        public int GetMaxID(string FIEldname,string tablename)        {            string strsql = "select max(" + FIEldname + ")+1 from " + tablename;            object obj = GetSingle(strsql);            if (obj == null)            {                return 1;            }	    return int.Parse(obj.ToString());        }        /// <summary>        /// 單值查詢，返回查詢結果(Object)        /// </summary>        /// <param name="sqlString"></param>        /// <returns></returns>        public object GetSingle(string sqlString)        {            var eventHandle = sqliteMessageEvent;            string msg = "";            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)))                        {                            msg = "WARN : sql Command Return null! [ " + sqlString + "]";                            if (eventHandle != null)                            {                                eventHandle(null,sqlString));                            }                            return null;                        }                        else                        {                            msg = "sql Command: " + sqlString + " Excute Success!";                            if (eventHandle != null)                            {                                eventHandle(null,sqlString));                            }                            return obj;                        }                    }                    catch (sqliteException e)                    {                        msg = "Execute sql Error Message: " + e.Message;                        if (eventHandle != null)                        {                            eventHandle(null,sqlString));                        }                        connection.Close();                        return null;                    }                    finally                    {                        connection.Close();                        cmd.dispose();                    }                                    }            }        }        /// <summary>        /// 執行多條sql語句，實現數據庫事務        /// </summary>        /// <param name="sqlStringList"></param>        public voID ExcutesqlTran(ArrayList sqlStringList)        {            var eventHandle = sqliteMessageEvent;            string msg = "";            using (sqliteConnection conn = new sqliteConnection(connectionString))            {                conn.open();                sqliteCommand cmd = new sqliteCommand();                cmd.Connection = conn;                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();                            msg = "sql Command: " + strsql + " Excute Success!";                            if (eventHandle != null)                            {                                eventHandle(null,strsql));                            }                        }                        else                        {                            msg = "Execute sql Error Message: strsql.Trim().Length=" + strsql.Trim().Length.ToString();                            if (eventHandle != null)                            {                                eventHandle(null,strsql));                            }                        }                    }                    tx.Commit();                }                catch (sqliteException ex)                {                    tx.Rollback();                    msg = "Execute sql Error Message: " + ex.Message;                    if (eventHandle != null)                    {                        eventHandle(null,"[ExcutesqlTran]"));                    }                }                finally                {                    conn.Close();                    cmd.dispose();                }            }        }        /// <summary>        /// 執行單條sql語句，返回值(Datatable)        /// </summary>        /// <param name="sqlString"></param>        /// <returns></returns>        public Datatable SelectUse(string sqlString)        {            var eventHandle = sqliteMessageEvent;            string msg = "";            sqliteCommand cmd = null;            sqliteDataAdapter oda = null;            sqliteConnection connection = null;            Datatable dt;            try            {                connection = new sqliteConnection(connectionString);                cmd = new sqliteCommand(sqlString,connection);                connection.open();                dt = new Datatable();                cmd.Transaction = connection.BeginTransaction();                oda = new sqliteDataAdapter(cmd);                oda.Fill(dt);                msg = "sql Command: " + sqlString + " Excute Success!";                if (eventHandle != null)                {                    eventHandle(null,sqlString));                }                return dt;            }            catch (sqliteException ex)            {                msg = "Execute sql Error Message: " + ex.Message;                if (eventHandle != null)                {                    eventHandle(null,sqlString));                }                return null;            }            finally            {                connection.Close();                cmd.dispose();                oda.dispose();            }        }        /// <summary>        /// 測試DB連接        /// </summary>        /// <returns></returns>        public bool ConnectConfirm()        {            var sqlStr = "select 1+1 from A";   //A是sqlite DB中的表            var result = SelectUse(sqlStr);            if (result != null)            {                if (result.Rows.Count == 0)                {                    return false;                }                return true;            }            else            {                return false;            }        }        }/// <summary>    /// 回復事件    /// </summary>    public class sqliteMessageEventArg:EventArgs    {        public sqliteMessageType EventID { get; private set; }        public string EventData{get;private set;}        public string sqlCommand { get; private set; }        public sqliteMessageEventArg(sqliteMessageType type,string data,string Strsql)        {            EventID = type;            EventData = data;            sqlCommand = Strsql;        }    }    public enum sqliteMessageType    {        None = 0,Info = 1,Msg = 2,Error = 3,Errorsql = 4,Connectbroken = 5,Others = 9    }//=======================主界面================================        static voID Main(string[] args)        {            bHelpersqlite _DB = new DbHelpersqlite();            _DB.sqliteMessageEvent += new EventHandler<sqliteMessageEventArg>(_DB_sqliteMessageEvent);            string _sql = "select Seq,cstID,D_Time,flag from w_CSTinfo";            Datatable _dt=_DB.SelectUse(_sql);	    ... ...        }        /// <summary>        /// DB執行對象返回事件        /// </summary>        /// <param name="sender"></param>        /// <param name="e"></param>        voID _DB_sqliteMessageEvent(object sender,sqliteMessageEventArg e)        {            switch (e.EventID)            {                 case sqliteMessageType.Msg:                    MessageBox.Show(e.EventData);                    break;                case sqliteMessageType.Error:                    MessageBox.Show(e.EventData + ",sql: " + e.sqlCommand);                    break;                case sqliteMessageType.Errorsql:                    MessageBox.Show(e.EventData);                    break;                default:                    break;            }        }

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