c# - Lose MongoDB ObjectId value when passing through Actions -

in mvc controller, have code (after adding object, redirect user edit object):

    [privilegerequirement("db_admin")]     public actionresult add()     {         mongodatacontext dc = new mongodatacontext();          var model = new modelobj();         dc.models.insert(model);          return this.redirecttoaction("edit", new { pid = model.id, });     }      [privilegerequirement("db_admin")]     public actionresult edit(objectid? pid)     {         mongodatacontext dc = new mongodatacontext();          var model = dc.models.findonebyid(pid);         if (model == null)         {             session["error"] = "no model id found.";             return this.redirecttoaction("");         }          return this.view(model);     } 

however, pid null, making findonebyid return null. have debugged , made sure id had value when passing add action. moreover, tried adding testing parameter:

    [privilegerequirement("db_admin")]     public actionresult add()     {         mongodatacontext dc = new mongodatacontext();          var model = new modelobj();         dc.models.insert(model);          return this.redirecttoaction("edit", new { pid = model.id, test = 10 });     }      [privilegerequirement("db_admin")]     public actionresult edit(objectid? pid, int? test)     {         mongodatacontext dc = new mongodatacontext();          var model = dc.models.findonebyid(pid);         if (model == null)         {             session["error"] = "no model id found.";             return this.redirecttoaction("");         }          return this.view(model);     } 

when debug, received test parameter in edit action value of 10 correctly, pid null. please tell me did wrong, , how solve problem?

i suspect objectid not serializing/deserializing correctly. given doesn't make great webapi anyway, use string , convert within method objectid via parse method (or use tryparse):

public actionresult edit(string id, int? test) {     // might need error handling here .... :)     var oid = objectid.parse(id);  } 

you can use tostring on objectid convert string calling:

var pid = model.id.tostring();