获取web.config配置文件的sectionGroup

1）web.config 文件内容如下：

<configuration>
  <configSections>
    <sectionGroup name="KaiXinSectionGroup">
      <section name="KaiXinSection" type="WebApplication1.RewriterConfigSection"/>   <!--type 为类RewriterConfigSection的路径-->
    </sectionGroup>
  </configSections>
    <system.web>
        <compilation debug="true" targetFramework="4.0" />
    </system.web>
  <KaiXinSectionGroup>
    <KaiXinSection>
      <add key="AppKey" value=""/>
      <add key="AppSecret" value=""/>
          <add key="SCOPE" value="basic"/>
    </KaiXinSection>
  </KaiXinSectionGroup>
</configuration>

2）添加一个类文件ConfigurationHelper.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Configuration;

namespace WebApplication1
{
    public class ConfigurationHelper
    {
    }

    public class RewriterConfigSection : ConfigurationSection
    {
        [ConfigurationProperty("", IsDefaultCollection = true)]
        public RewriterRuleElementCollection MySection
        {
            get { return (RewriterRuleElementCollection)base[""]; }
        }
    }

    public class RewriterRuleElement : ConfigurationElement
    {
        [ConfigurationProperty("key", IsRequired = true)]
        public string Key
        {
            get { return (string)base["key"]; }
            set { base["key"] = value; }
        }
        [ConfigurationProperty("value", IsRequired = true)]
        public string Value
        {
            get { return (string)base["value"]; }
        }

    }
    public class RewriterRuleElementCollection : ConfigurationElementCollection
    {
        public RewriterRuleElementCollection()
        {
            RewriterRuleElement rrElement = CreateNewElement() as RewriterRuleElement;
            BaseAdd(rrElement);
        }
        protected override ConfigurationElement CreateNewElement()
        {
            return new RewriterRuleElement();
        }
        protected override object GetElementKey(ConfigurationElement element)
        {
            return ((RewriterRuleElement)element).Key;
        }

        protected override string ElementName
        {
            get
            {
                return "add";
            }
        }
        public override ConfigurationElementCollectionType CollectionType
        {
            get
            {
                return ConfigurationElementCollectionType.BasicMap;
            }
        }
        public RewriterRuleElement this[int index]
        {
            get { return (RewriterRuleElement)BaseGet(index); }
        }
        public new RewriterRuleElement this[string name]
        {
            get { return (RewriterRuleElement)BaseGet(name); }
        }

    }
}

3）获取SessionGroup里的值

   public RewriterConfigSection Section { get; set; }
        protected void Button1_Click(object sender, EventArgs e)
        {

            Section = (RewriterConfigSection)ConfigurationManager.GetSection("KaiXinSectionGroup/KaiXinSection");
            string a = Section.MySection["AppKey"].Value;
            string b = Section.MySection["AppSecret"].Value;
            string c = Section.MySection["SCOPE"].Value;
        }