C#封装的Sqlite访问类

using System;
using System.Collections;
using System.Collections.Specialized;
using System.Data;
using System.Configuration;
using System.Data.SQLite;
namespace DAL
{
    internal abstract class DbHelperSQLite
    {      
        public static string connectionString = "Data Source=" + AppDomain.CurrentDomain.BaseDirectory + @"dataleaf.db;Version=3;";
        public DbHelperSQLite()
        {
        }
  
  
        #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,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>
        /// 执行多条SQL语句，实现数据库事务。
        /// </summary>
        /// <param name="SQLStringList">多条SQL语句</param>    
        public static void ExecuteSqlTran(ArrayList SQLStringList)
        {
            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();
                        }
                    }
                    tx.Commit();
                }
                catch (System.Data.SQLite.SQLiteException E)
                {
                    tx.Rollback();
                    throw new Exception(E.Message);
                }
            }
        }
        /// <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>
        /// 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,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
        /// </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);
            }
  
        }
        /// <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");
                }
                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
                    {
                        trans.Rollback();
                        throw;
                    }
                }
            }
        }
  
  
        /// <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,cmdParms);
                        object obj = cmd.ExecuteScalar();
                        cmd.Parameters.Clear();
                        if ((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
        /// </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,cmdParms);
                SQLiteDataReader myReader = cmd.ExecuteReader();
                cmd.Parameters.Clear();
                return myReader;
            }
            catch (System.Data.SQLite.SQLiteException e)
            {
                throw new Exception(e.Message);
            }
  
        }
  
        /// <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,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;
                }
            }
        }
  
  
        private 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 parm in cmdParms)
                    cmd.Parameters.Add(parm);
            }
        }
  
        #endregion
    }
}