C#中读取App.config配置文件代码实例

<?xml version="1.0" encoding="utf-8" ?><configuration> <connectionStrings>  <add name="conn" connectionString="this is connection string"/> </connectionStrings> <appSettings>  <add key="key1" value="value1" />  <add key="key2" value="value2" /> </appSettings></configuration>

using System;using System.Collections.Generic;using System.Collections;using System.Linq;using System.Text;using System.Configuration;namespace AppConfig{  class Program  {    static void Main(string[] args)    {      Console.WriteLine("ConnectionStrings:");      // ConfigurationManager.ConnectionStrings是一个ConnectionStringSettingsCollection对象      // 按数字循环得到一个个ConnectionStringSettings对象      // 每个ConnectionStringSettings对象有Name和ConnectionString属性      for (int i = 0; i < ConfigurationManager.ConnectionStrings.Count; i++)      {        string name = ConfigurationManager.ConnectionStrings[i].Name;        string connectionString = ConfigurationManager.ConnectionStrings[i].ConnectionString;        Console.WriteLine(i.ToString() + ". " + name + " = " + connectionString);      }      //也可以如下操作，使用ConnectionStringSettings类型来进行foreach遍历      foreach (ConnectionStringSettings conn in ConfigurationManager.ConnectionStrings)      {        string name = conn.Name;        string connectionString = conn.ConnectionString;        Console.WriteLine(name + " = " + connectionString);      }      //直接获取conn的值      Console.WriteLine("/r/nGet the value of the node named /"conn/":");      Console.WriteLine(ConfigurationManager.ConnectionStrings["conn"].ConnectionString);      Console.WriteLine("");      Console.WriteLine("AppSettings:");      //AppSettings是NameValueConnection类型，使用AllKeys返回一个所有Key组成的字符串数组      string[] keys = ConfigurationManager.AppSettings.AllKeys;      for (int i = 0; i < keys.Length; i++)      {        string key = keys[i];        //通过Key来索引Value        string value = ConfigurationManager.AppSettings[key];        Console.WriteLine(i.ToString() + ". " + key + " = " + value);      }      // 没有NameValuePair这样的对象，所以无法使用foreach来进行循环      //直接获取key1的值      Console.WriteLine("/r/nGet the value of the key named /"key1/":");      Console.WriteLine(ConfigurationManager.AppSettings["key1"]);      //pause the process      Console.ReadKey();    }  }}