/// <summary>
 /// 获取指定前缀的所有配置
 /// </summary>
 /// <param name="prefix">前缀 符号.可有可无</param>
 /// <returns>去掉前缀的配置项</returns>
 public Dictionary <string, string> GetByprefix(string prefix)
 {
     if (!prefix.EndsWith("."))
     {
         prefix = prefix + ".";
     }
     return(ConfigDictionary.Where(dic => dic.Key.StartsWith(prefix)).ToDictionary(dic => dic.Key.Remove(0, prefix.Length), dic => dic.Value));
 }