Static Properties, directly remove IIS from HTTP Error 503 service unavailable

Attribute has a benefit. You can perform some special processing during get. For example, if a default value is returned, this feature attracts me to change static fields to static attributes. The Code is as follows:

  Public   static   string   subscription number {  Get  {  If  ( string  . isnullorempty (subscription No.) {subscription No.  =  "  Jinhe diary  "  ;}  return   subscription number ;}  set  { subscription number =< span style =" color: #000000; "> value ;} 

HTTP Error 503 service unavailable