c# - Avoiding default constructors and public property setters -

i'm working on project signalr, , i've got objects i'm going passing along through it. these objects explicitly created in back-end code, , i'd able enforce immutability , invariants on them. i'm running issue signalr requires me (well, newtonsoft.json), have default, no-args constructor , public setters on properties in order serialize , deserialize them on wire.

here's contrived example:

public class message{     public string text {get;set;}     public int awesomeness {get;set;} } 

what i'd like, more along these lines (it should have readonly private fields , getter-only properties immutable, poco no methods, enough)

public class message {     public string text {get;private set;}     public int awesomeness {get;private set;}     public message( string msg, int awesome){         if (awesome < 1 || awesome > 5){             throw new argumentoutofrangeexception("awesome");         }         text = msg;         awesomeness = awesome;     } } 

if that, though, object can't deserialized signalr .net client library. can chuck default constructor in there, , make setters public, have remember not use them in code, , make sure no 1 else on team uses them without understanding.

i've kicked around idea of doing this, mark default constructor should never explicitly used:

[obsolete("bad! don't this!") public message(){} 

but can't use obsolete attribute on setter of property.

if wanted to, separate out "real" object dto representation , convert between them, i'm not psyched write bunch of boilerplate , introduce layer.

is there i'm overlooking, or need bite bullet , deal it?

if class not have public parameterless constructor, have single public constructor parameters, json.net call constructor, matching constructor arguments json properties name using reflection , using default values missing properties. matching name case-insensitive, unless there multiple matches differ in case, in case match becomes case sensitive. if do:

public class message {     public string text { get; private set; }     public int awesomeness { get; private set; }     public message(string text, int awesomeness)     {         if (awesomeness < 1 || awesomeness > 5)         {             throw new argumentoutofrangeexception("awesome");         }         this.text = text;         this.awesomeness = awesomeness;     } } 

you able serialize , deserialize class json.net.

prototype fiddle.

if class has multiple public constructors, parameters, can mark 1 use [jsonconstructor], e.g.:

public class message {     public string text { get; private set; }     public int awesomeness { get; private set; }      public message(string text)         : this(text, 1)     {     }      [jsonconstructor]     public message(string text, int awesomeness)     {         if (awesomeness < 1 || awesomeness > 5)         {             throw new argumentoutofrangeexception("awesome");         }         this.text = text;         this.awesomeness = awesomeness;     } } 

see jsonserializersettings.constructorhandling tells json.net whether prefer non-public parameterless constructor on single public constructor parameters.