private void UpdateContent()
        {
            StringBuilder stringBuilder = new StringBuilder();

            foreach (var key in Keys)
            {
                stringBuilder.AddKeyValue(key, this[key], this.separatorSymbol, this.pairSymbol);
            }
            Content = stringBuilder.ToString();
        }
        static public StringBuilder AppendObject(this StringBuilder it, object obj, bool isReturnXml)
        {
            if (obj == null)
            {
                return(it);
            }
            var    type = obj.GetType();
            string sb   = (isReturnXml) ? "\"" : "";


            foreach (var prop in type.GetProperties(System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.GetProperty | System.Reflection.BindingFlags.Instance))
            {
                //if (!prop.CanRead) continue;
                var value = prop.GetValue(obj, null);
                it.AddKeyValue(prop.Name, sb + value + sb);
            }
            if (isReturnXml)
            {
                it.Insert(0, " ").Insert(0, type.Name).Insert(0, "<").Append("\\>");
            }
            return(it);
        }
 static public StringBuilder AddKeyValue(this StringBuilder it, string key, object value)
 {
     return(it.AddKeyValue(key, value, DefaultSeparatorSymbol, DefaultPairSymbol));
 }