SQLite 帮助类

public static class SqliteHelper
{
	/// <summary>    
	/// 获得连接对象   
	/// </summary>    
	/// <returns>SQLiteConnection</returns>       
	public static SQLiteConnection GetSQLiteConnection()
	{
		//Sqlite数据库地址<br>            
		string str = AppDomain.CurrentDomain.BaseDirectory;
		var con = new SQLiteConnection("Data Source=" + str + "DataBass\\InfoServiceDbB.db");
		return con;
	}

	/// <summary>
	/// 准备操作命令参数
	/// </summary>
	/// <param name="cmd">SQLiteCommand</param>
	/// <param name="conn">SQLiteConnection</param>
	/// <param name="cmdText">Sql命令文本</param>
	/// <param name="data">参数数组</param>
	private static void PrepareCommand(SQLiteCommand cmd, SQLiteConnection conn, string cmdText, Dictionary<String, String> data)
	{
		if (conn.State != ConnectionState.Open)
			conn.Open();
		cmd.Parameters.Clear();
		cmd.Connection = conn;
		cmd.CommandText = cmdText;
		cmd.CommandType = CommandType.Text;
		cmd.CommandTimeout = 30;
		if (data != null && data.Count >= 1)
		{
			foreach (KeyValuePair<String, String> val in data)
			{
				cmd.Parameters.AddWithValue(val.Key, val.Value);
			}
		}
	}

	/// <summary>
	/// 查询，返回DataSet
	/// </summary>
	/// <param name="cmdText">Sql命令文本</param>
	/// <param name="data">参数数组</param>
	/// <returns>DataSet</returns>
	public static DataSet ExecuteDataset(string cmdText, Dictionary<string, string> data)
	{
		var ds = new DataSet();
		using (SQLiteConnection connection = GetSQLiteConnection())
		{
			var command = new SQLiteCommand();
			PrepareCommand(command, connection, cmdText, data);
			var da = new SQLiteDataAdapter(command);
			da.Fill(ds);
		}
		return ds;
	}

	/// <summary>
	/// 查询，返回DataTable
	/// </summary>
	/// <param name="cmdText">Sql命令文本</param>
	/// <param name="data">参数数组</param>
	/// <returns>DataTable</returns>
	public static DataTable ExecuteDataTable(string cmdText, Dictionary<string, string> data)
	{
		var dt = new DataTable();
		using (SQLiteConnection connection = GetSQLiteConnection())
		{
			var command = new SQLiteCommand();
			PrepareCommand(command, connection, cmdText, data);
			SQLiteDataReader reader = command.ExecuteReader();
			dt.Load(reader);
		}
		return dt;
	}

	/// <summary>
	/// 返回一行数据
	/// </summary>
	/// <param name="cmdText">Sql命令文本</param>
	/// <param name="data">参数数组</param>
	/// <returns>DataRow</returns>
	public static DataRow ExecuteDataRow(string cmdText, Dictionary<string, string> data)
	{
		DataSet ds = ExecuteDataset(cmdText, data);
		if (ds != null && ds.Tables.Count > 0 && ds.Tables[0].Rows.Count > 0)
			return ds.Tables[0].Rows[0];
		return null;
	}

	/// <summary>
	/// 执行数据库操作
	/// </summary>
	/// <param name="cmdText">Sql命令文本</param>
	/// <param name="data">传入的参数</param>
	/// <returns>返回受影响的行数</returns>
	public static int ExecuteNonQuery(string cmdText, Dictionary<string, string> data)
	{
		using (SQLiteConnection connection = GetSQLiteConnection())
		{
			var command = new SQLiteCommand();
			PrepareCommand(command, connection, cmdText, data);
			return command.ExecuteNonQuery();
		}
	}

	/// <summary>
	/// 返回SqlDataReader对象
	/// </summary>
	/// <param name="cmdText">Sql命令文本</param>
	/// <param name="data">传入的参数</param>
	/// <returns>SQLiteDataReader</returns>
	public static SQLiteDataReader ExecuteReader(string cmdText, Dictionary<string, string> data)
	{
		var command = new SQLiteCommand();
		SQLiteConnection connection = GetSQLiteConnection();
		try
		{
			PrepareCommand(command, connection, cmdText, data);
			SQLiteDataReader reader = command.ExecuteReader(CommandBehavior.CloseConnection);
			return reader;
		}
		catch
		{
			connection.Close();
			command.Dispose();
			throw;
		}
	}

	/// <summary>
	/// 返回结果集中的第一行第一列，忽略其他行或列
	/// </summary>
	/// <param name="cmdText">Sql命令文本</param>
	/// <param name="data">传入的参数</param>
	/// <returns>object</returns>
	public static object ExecuteScalar(string cmdText, Dictionary<string, string> data)
	{
		using (SQLiteConnection connection = GetSQLiteConnection())
		{
			var cmd = new SQLiteCommand();
			PrepareCommand(cmd, connection, cmdText, data);
			return cmd.ExecuteScalar();
		}
	}

	/// <summary>
	/// 分页查询
	/// </summary>
	/// <param name="recordCount">总记录数</param>
	/// <param name="pageIndex">页牵引</param>
	/// <param name="pageSize">页大小</param>
	/// <param name="cmdText">Sql命令文本</param>
	/// <param name="countText">查询总记录数的Sql文本</param>
	/// <param name="data">命令参数</param>
	/// <returns>DataSet</returns>
	public static DataSet ExecutePager(ref int recordCount, int pageIndex, int pageSize, string cmdText, string countText, Dictionary<string, string> data)
	{
		if (recordCount < 0)
			recordCount = int.Parse(ExecuteScalar(countText, data).ToString());
		var ds = new DataSet();
		using (SQLiteConnection connection = GetSQLiteConnection())
		{
			var command = new SQLiteCommand();
			PrepareCommand(command, connection, cmdText, data);
			var da = new SQLiteDataAdapter(command);
			da.Fill(ds, (pageIndex - 1) * pageSize, pageSize, "result");
		}
		return ds;
	}

	/// <summary>
	/// 清除空间
	/// </summary>
	public static void ResetDataBass()
	{
		using (SQLiteConnection conn = GetSQLiteConnection())
		{
			var cmd = new SQLiteCommand();

			if (conn.State != ConnectionState.Open)
				conn.Open();
			cmd.Parameters.Clear();
			cmd.Connection = conn;
			cmd.CommandText = "vacuum";
			cmd.CommandType = CommandType.Text;
			cmd.CommandTimeout = 30;
			cmd.ExecuteNonQuery();
		}
	}

}