在配置文件中获取字符串

1、在web.config文件中加
<configuration>
 <appSettings>
  <add key="ConnectionString" value="Data Source=(local);Initial Catalog=MyData;User Id=sa;Password=sa;Connect Timeout=180;Enlist=true;Pooling=true;Max Pool Size = 300;Min Pool Size = 5;Connection Lifetime=200;packet size=4096"/>
 </appSettings>
</configuration>

2、添加.Net引用System.Configuration 的Dll

3、声明using System.Configuration;

4、public static string connectionString = ConfigurationManager.AppSettings["ConnectionString"];

适合于不同工程之间互相调用。