C#访问sqllite数据库的数据库访问类

         最近在一个项目中需要用到sqllite数据库，因此根据项目需要收集了sqllite的数据库访问类的资料，然后根据实际需求进行了改装，并

成功的运用到了项目中，现在项目也成功上线，特将此代码分享给大家：

         /// <summary>
    /// 数据库操作抽象
    /// </summary>
    public interface IDataAccess
    {
        /// <summary>
        /// 打开
        /// </summary>
        void Open();
        /// <summary>
        /// 关闭
        /// </summary>
        void Close();

        /// <summary>
        /// 执行 增 删 改 查
        /// </summary>
        /// <param name="sql">Sql语句</param>
        /// <param name="queryParameter">参数</param>
        int ExecuteNonQuery(string sql, QueryParameter[] queryParameter);

        /// <summary>
        /// 查询某一个值
        /// </summary>
        /// <param name="sql">Sql语句</param>
        /// <param name="parameters">参数</param>
        /// <returns>Object</returns>
        object GetScalar(string sql, QueryParameter[] parameters);

        /// <summary>
        /// 查询多条条数据
        /// </summary>
        /// <param name="sql">Sql语句</param>
        /// <param name="parameters">参数</param>
        /// <returns>DataTable</returns>
        DataTable GetTable(string sql, QueryParameter[] parameters);

        /// <summary>
        /// 查询多条值
        /// </summary>
        /// <param name="sql">Sql语句</param>
        /// <param name="parameters">参数</param>
        /// <returns>DataReader</returns>
        IDataReader GetReader(string sql, QueryParameter[] parameters);

        /// <summary>
        /// 开始事务
        /// </summary>
        void BeginTran();
        /// <summary>
        /// 提交事务
        /// </summary>
        void CommitTran();
        /// <summary>
        ///  回滚事务
        /// </summary>
        void RollBackTran();

    }

public class SqlLiteDalHelper : IDataAccess
    {
        private readonly SQLiteConnection _connection;
        private SQLiteTransaction _tran;
        public SqlLiteDalHelper(string constr)
        {
            _connection = new SQLiteConnection(constr);
        }

        public void Open()
        {
            if (this._connection == null || this._connection.State == ConnectionState.Closed)
            {
                try
                {
                    _connection.Open();
                }
                catch (ArgumentException)
                {
                    throw;
                }
            }
        }

        public void Close()
        {
            if (this._connection != null || _tran != null)
            {
                _connection.Close();
            }
        }

        public int ExecuteNonQuery(string sql, QueryParameter[] queryParameter)
        {
            SQLiteCommand cmd = new SQLiteCommand();
            PrepareCommond(cmd, CommandType.Text, queryParameter, sql);
            Open();
            int i = cmd.ExecuteNonQuery();
            cmd.Parameters.Clear();
            Close();
            return i;
        }

        public object GetScalar(string sql, QueryParameter[] parameters)
        {
            SQLiteCommand cmd = new SQLiteCommand();
            PrepareCommond(cmd, CommandType.Text, parameters, sql);
            Open();
            object obj = cmd.ExecuteScalar();
            cmd.Parameters.Clear();
            Close();
            return obj;
        }

        public System.Data.DataTable GetTable(string sql, QueryParameter[] parameters)
        {
            DataTable dt = new DataTable();
            SQLiteCommand cmd = new SQLiteCommand();
            PrepareCommond(cmd, CommandType.Text, parameters, sql);
            Open();
            SQLiteDataAdapter sda = new SQLiteDataAdapter(cmd);
            sda.Fill(dt);
            cmd.Parameters.Clear();
            Close();
            return dt;
        }

        public System.Data.IDataReader GetReader(string sql, QueryParameter[] parameters)
        {
            SQLiteCommand cmd = new SQLiteCommand();
            PrepareCommond(cmd, CommandType.Text, parameters, sql);
            Open();
            SQLiteDataReader dr = cmd.ExecuteReader();
            cmd.Parameters.Clear();
            Close();
            return dr;
        }

        public void BeginTran()
        {
            this._tran = this._connection.BeginTransaction();
        }

        public void CommitTran()
        {
            this._tran.Commit();
        }

        public void RollBackTran()
        {
            this._tran.Rollback();
        }

        private void PrepareCommond(SQLiteCommand cmd, CommandType commandType, QueryParameter[] parameters, string commandtext)
        {
            cmd.CommandType = commandType;
            cmd.CommandText = commandtext;
            cmd.Connection = _connection;
            cmd.Transaction = this._tran;
            if (parameters != null && parameters.Length > 0)
            {
                for (int i = 0; i < parameters.Length; i++)
                {
                    cmd.Parameters.AddWithValue(parameters[i].Name, parameters[i].Value);
                }
            }
        }
    }