public class ConfigOperator
  {
    #region 从配置文件获取Value
    /// <summary>
    /// 从配置文件获取Value
    /// </summary>
    /// <param name="key">配置文件中key字符串</param>
    /// <returns></returns>
    public static string GetValueFromConfig(string key)
    {
      try
      {
        Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
        //获取AppSettings的节点 
        AppSettingsSection appsection = (AppSettingsSection)config.GetSection("appSettings");
        return appsection.Settings[key].Value;
      }
      catch
      {
        return "";
      }
    }
    #endregion

    #region 设置配置文件
    /// <summary>
    /// 设置配置文件
    /// </summary>
    /// <param name="key">配置文件中key字符串</param>
    /// <param name="value">配置文件中value字符串</param>
    /// <returns></returns>
    public static bool SetValueFromConfig(string key, string value)
    {
      try
      {
        //打开配置文件 
        Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
        //获取AppSettings的节点 
        AppSettingsSection appsection = (AppSettingsSection)config.GetSection("appSettings");
        appsection.Settings[key].Value = value;
        config.Save();

        return true;
      }
      catch
      {
        return false;
      }
    }
    #endregion