C#封装的Sqlite访问类实例

本文实例讲述了C#封装的Sqlite访问类。分享给大家供大家参考。具体分析如下：

C#封装的Sqlite访问类，要访问Sqlite这下简单了，直接调用此类中的方法即可

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, null)) || (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, null)) || (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, params SQLiteParameter[] cmdParms)
 {
  using (SQLiteConnection connection = new SQLiteConnection(connectionString))
  {
   using (SQLiteCommand cmd = new SQLiteCommand())
   {
    try
    {
     PrepareCommand(cmd, connection, null, SQLString, cmdParms);
     object obj = cmd.ExecuteScalar();
     cmd.Parameters.Clear();
     if ((Object.Equals(obj, null)) || (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, connection, null, SQLString, 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, connection, null, SQLString, 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
}
}

希望本文所述对大家的C#程序设计有所帮助。