SQL SERVER-通过配置文件获得连接字符串的两种方式

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <startup> 
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.6.1" />
    </startup>
  <appSettings>
    <add key="connStr" value="server=.;database=mydbtest;uid=sa;pwd=Server2012"/>
  </appSettings>
  <connectionStrings>
    <add name="connStr" connectionString="server=.;database=mydbtest;uid=sa;pwd=Server2012" providerName="System.Data.SqlClient"/>
  </connectionStrings>
</configuration>

 

public class ConnectionStringHelper
    {
        public static string GetConnectionString()
        {
           //return ConfigurationManager.AppSettings["connStr"].ToString()
            return ConfigurationManager.ConnectionStrings["connStr"].ConnectionString;
        }
    }