C# SQLite实用帮助类:SQLiteHelper

依赖:System.Data.SQLite.dll

SQLiteHelper代码:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO; 
using System.Data; 
using System.Data.SQLite;

namespace SQLite {

    /// 
 
    /// SQLite数据库操作帮助类
    /// 提供一系列方便的调用:
    /// Execute,Save,Update,Delete...
    /// 
    /// 不是线程安全的
    /// 
    /// @author pcenshao
    /// 
    public class SQLiteHelper { 

        private bool _showSql = true;

        /// 

        /// 是否输出生成的SQL语句
        /// 
        public bool ShowSql {
            get {
                return this._showSql;
            }
            set {
                this._showSql = value; 
            }
        }

        private readonly string _dataFile;

        private SQLiteConnection _conn; 

        public SQLiteHelper(string dataFile) {
            if (dataFile == null)
                throw new ArgumentNullException("dataFile=null");
            this._dataFile = dataFile;             
        }

        /// 

        /// 打开SQLiteManager使用的数据库连接
        /// 
        public void Open() {
            this._conn = OpenConnection(this._dataFile); 
        }

        public void Close() {
            if (this._conn != null) {
                this._conn.Close();
            }
        }

        /// 

        /// 安静地关闭连接,保存不抛出任何异常
        /// 
        public void CloseQuietly() {
            if (this._conn != null) {
                try {
                    this._conn.Close();
                } catch { }
            }
        }

        /// 

        /// 创建一个连接到指定数据文件的SQLiteConnection,并Open
        /// 如果文件不存在,创建之
        /// 
        /// 
        /// 
        public static SQLiteConnection OpenConnection(string dataFile) {
            if (dataFile == null)
                throw new ArgumentNullException("dataFile=null");

            if (!File.Exists(dataFile)) {
                SQLiteConnection.CreateFile(dataFile);
            }

            SQLiteConnection conn = new SQLiteConnection();
            SQLiteConnectionStringBuilder conStr = new SQLiteConnectionStringBuilder();
            conStr.DataSource = dataFile;
            conn.ConnectionString = conStr.ToString(); 
            conn.Open();
            return conn; 
        }

        /// 

        /// 读取或设置SQLiteManager使用的数据库连接
        /// 
        public SQLiteConnection Connection {
            get {
                return this._conn;
            }
            set {
                if (value == null) {
                    throw new ArgumentNullException(); 
                }
                this._conn = value; 
            }
        }

        protected void EnsureConnection() {
            if (this._conn == null) {
                throw new Exception("SQLiteManager.Connection=null");
            }
        }

        public string GetDataFile() {
            return this._dataFile; 
        }

        /// 

        /// 判断表table是否存在
        /// 
        /// 
        /// 
        public bool TableExists(string table) {
            if (table == null)
                throw new ArgumentNullException("table=null");
            this.EnsureConnection();
            // SELECT count(*) FROM sqlite_master WHERE type='table' AND name='test';
            SQLiteCommand cmd = new SQLiteCommand("SELECT count(*) as c FROM sqlite_master WHERE type='table' AND name=@tableName ");
            cmd.Connection = this.Connection;
            cmd.Parameters.Add(new SQLiteParameter("tableName", table)); 
            SQLiteDataReader reader = cmd.ExecuteReader();
            reader.Read();
            int c = reader.GetInt32(0); 
            reader.Close();
            reader.Dispose();
            cmd.Dispose();
            //return false;
            return c == 1;  
        }

        /// 

        /// 执行SQL,返回受影响的行数
        /// 可用于执行表创建语句
        /// paramArr == null 表示无参数
        /// 
        /// 
        /// 
        public int ExecuteNonQuery(string sql,SQLiteParameter[] paramArr) {
            if (sql == null) {
                throw new ArgumentNullException("sql=null");
            }
            this.EnsureConnection();

            if (this.ShowSql) {
                Console.WriteLine("SQL: " + sql);
            }

            SQLiteCommand cmd = new SQLiteCommand();
            cmd.CommandText = sql;
            if (paramArr != null) {
                foreach (SQLiteParameter p in paramArr) {
                    cmd.Parameters.Add(p);
                }
            }
            cmd.Connection = this.Connection;
            int c = cmd.ExecuteNonQuery();
            cmd.Dispose(); 
            return c; 
        }

        /// 

        /// 执行SQL,返回SQLiteDataReader
        /// 返回的Reader为原始状态,须自行调用Read()方法
        /// paramArr=null,则表示无参数
        /// 
        /// 
        /// 
        /// 
        public SQLiteDataReader ExecuteReader(string sql,SQLiteParameter[] paramArr) {
            return (SQLiteDataReader)ExecuteReader(sql, paramArr, (ReaderWrapper)null); 
        }

        /// 

        /// 执行SQL,如果readerWrapper!=null,那么将调用readerWrapper对SQLiteDataReader进行包装,并返回结果
        /// 
        /// 
        /// null 表示无参数
        /// null 直接返回SQLiteDataReader
        /// 
        public object ExecuteReader(string sql, SQLiteParameter[] paramArr, ReaderWrapper readerWrapper) {
            if (sql == null) {
                throw new ArgumentNullException("sql=null");
            }
            this.EnsureConnection();

            SQLiteCommand cmd = new SQLiteCommand(sql, this.Connection);
            if (paramArr != null) {
                foreach (SQLiteParameter p in paramArr) {
                    cmd.Parameters.Add(p);
                }
            }
            SQLiteDataReader reader = cmd.ExecuteReader(); 
            object result = null;
            if (readerWrapper != null) {
                result = readerWrapper(reader);
            } else {
                result = reader; 
            }
            reader.Close();
            reader.Dispose(); 
            cmd.Dispose();
            return result; 
        }

        /// 

        /// 执行SQL,返回结果集,使用RowWrapper对每一行进行包装
        /// 如果结果集为空,那么返回空List (List.Count=0)
        /// rowWrapper = null时,使用WrapRowToDictionary
        /// 
        /// 
        /// 
        /// 
        /// 
        public List