sqlitehelper封装

appsettings	<configuration>     <appSettings>         <add key="ConnectionString" value="Data Source=.;Initial Catalog=Test;User Id=sa;Password=123;" />     </appSettings> </configuration>
connectionStrings	<connectionStrings> <add name="ConnectionString" connectionString="Data Source=.;Initial Catalog=Test;Persist Security Info=True;User ID=sa;Password=123;" providerName="System.Data.SqlClient"/>   </connectionStrings>

APP.CONGIG文件

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<!--<connectionStrings>

<add connectionString="data sourse = cater.db;version =3;" name="constr"/> --><!--连接字符串配置文件，字符串名字--><!--
</connectionStrings>-->

<appSettings>

<add key="constr" value=" data source=cater.db;version =3;"/>
</appSettings>

<!--<connectionStrings >

<add name="constr" connectionString="data source =cater.db;version =3;"/>
</connectionStrings>-->

</configuration>

代码：

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

namespace restaurant.DAL
{
public class SQLiteHelper
{ //连接字符串
private static readonly string str = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
string dd = ConfigurationManager.AppSettings["constr"].ToString();

/// <summary>
/// 增删改
/// </summary>
/// <param name="sql">sql语句</param>
/// <param name="param">参数</param>
/// <returns>返回受影响的行数</returns>
public static int ExecuteNonQuery(string sql, params SQLiteParameter[] param)
{
using (SQLiteConnection conn = new SQLiteConnection(str))
{
using (SQLiteCommand cmd = new SQLiteCommand(sql, conn))
{
conn.Open();
if (param != null)
{
cmd.Parameters.AddRange(param);
}
return cmd.ExecuteNonQuery();
}
}
}
/// <summary>
/// 查询
/// </summary>
/// <param name="sql">sql 语句</param>
/// <param name="param">参数</param>
/// <returns>返回 首行首列</returns>
public static object ExecuteScale(string sql, params SQLiteParameter[] param)
{
using (SQLiteConnection conn = new SQLiteConnection(str))
{
using (SQLiteCommand cmd = new SQLiteCommand(sql, conn))
{
conn.Open();
if (param != null)
{
cmd.Parameters.AddRange(param);
}
return cmd.ExecuteScalar();
}
}
}

/// <summary>
///多行查询
/// </summary>
/// <param name="sql">sql语句</param>
/// <param name="param">参数</param>
/// <returns>ExecuteReader</returns>
public static SQLiteDataReader ExecueDataReader(string sql, params SQLiteParameter[] param)
{
SQLiteConnection conn = new SQLiteConnection(str);
using (SQLiteCommand cmd = new SQLiteCommand(sql, conn))
{
if (param != null)
{
cmd.Parameters.AddRange(param);
}
try
{
conn.Open();
return cmd.ExecuteReader(System.Data.CommandBehavior.CloseConnection);
}
catch (Exception ex)
{
conn.Close();
cmd.Dispose();
throw ex;
}
}
}
/// <summary>
/// 查询多行数据
/// </summary>
/// <param name="sql">sql语句</param>
/// <param name="param">sql参数</param>
/// <returns>一个表</returns>
public static DataTable ExecuteTable(string sql, params SQLiteParameter[] param)
{
DataTable dt = new DataTable();
using (SQLiteDataAdapter sda = new SQLiteDataAdapter(sql, str))
{
if (param != null)
{
sda.SelectCommand.Parameters.AddRange(param);
}
sda.Fill(dt);
}
return dt;
}
}
}