asp.net mvc 2 - Model binding issue in LINQ to SQL -

i starting work linq, , pretty familiar mvc. have typed view updating record. have done creation:

this works fine, , creates record in database:

public actionresult create(tablemodel tablemodel) {     dbdatacontext db = new dbdatacontext();     if (modelstate.isvalid)     {         db.tablemodel.insertonsubmit(tablemodel);         db.submitchanges();     } } 

but when trying update:

public actionresult manage(tablemodel tablemodel) {     dbdatacontext db = new dbdatacontext();     if (modelstate.isvalid)     {         db.submitchanges();     } } 

this fails, in sense not update record in database. no actual error/exception occurs, , can step through fine.

i sure missing something, cannot find what. appreciate on matter.

update
did notice if record using datacontext:

dbdatacontext db = new dbdatacontext(); var m = db.tablemodels.single(m => m.id == 1); m.name = "updatedname"; db.submitchanges(); 

this update, assume somehow not binding model linq context.

my solution
found need retrieve object , update form. simple enough.

[httppost] public actionresult manage(int id, formcollection form) {     dbsdatacontext db = new dbsdatacontext();     var t= db.tablemodels.single(b => b.id == id);     updatemodel(t);     if (modelstate.isvalid)     {         db.submitchanges();     }     return view(t); } 

you should re-query original tablemodel, map updated row , update.

perhaps (example only, not knowing schema):

var originaltablemodel = db.getbyid( tablemodel.id); originaltablemodel.firstname = tablemodel.firstname; db.submitchanges();