找不到ConfigurationManager类

1.web.config

 

 <connectionStrings>
    <add  name="ConnectionString" connectionString="server=192.168.1.214; User ID=sa;password=tendency;database=GodErLang"/>
  </connectionStrings>

 

 

 

2.添加对System.Configuration.dll文件的引用

3.读取：

 

public static string ConnectionString
        {
            get
            {
                   return     ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
             }
        }