c# - Automapper - Convert string property to SelectList? -

i'm starting learn automapper in mvc project. have base entity "attendee" string field gender (possible values of "m" or "f").

i have basic mapping created between attendee , attendeeeditview objects. want convert "m" or "f" gender string on model side selectlist on viewmodel side, appropriate value selected in list.

i think need valueresolver this... here's i've written:

public class gendermenuresolver : valueresolver<attendee, selectlist> {     protected override selectlist resolvecore( attendee source ) {         list<object> items = new list<object>(){             new{ value = "f" , text = "female" },             new{ value = "m" , text = "male" }         };          string gender = source.gender ?? "";         string selectedvalue = new list<string>() { "m", "f" }.contains( gender.toupper() ) ? gender.toupper() : "";          selectlist gendermenu = new selectlist(             items,             "value",             "text",             selectedvalue         );          return gendermenu;     } } 

and mapping code:

mapper.createmap<attendee, attendeeeditview>() .formember( dest => dest.gender, opt => opt.resolveusing<gendermenuresolver>() );   list<attendeeeditview> viewmodel = mapper.map<list<attendeeeditview>>( attendees ); 

stepping through can see code executes , outputs proper selectlist. however, following error:

mapping types: selectlist -> selectlist system.web.mvc.selectlist -> system.web.mvc.selectlist

destination path: list`1[0].gender.gender

source value: system.web.mvc.selectlist

first, ".gender.gender" mapping seems incorrect.

but appears root issue... inner exception message reveals this:

"type 'system.web.mvc.selectlist' not have default constructor"

can me identify i'm doing wrong, or perhaps better approach should using? thanks.

i think you're making more difficult needs be. not needs mapped, in fact things selectlists shouldn't mapped because they're relevant view model, not model.

so, in view model like:

public string gender { get; set; }  public selectlist genderchoices {         {         return new selectlist(new list<selectlistitem>             {                 new selectlistitem { value = "m", text = "male" },                 new selectlistitem { value = "f", text = "female" }             }, "value", "text", gender);     }  } 

where gender mapped, genderchoices exist on view model.

then, in view:

@html.dropdownlistfor(m => m.gender, model.genderchoices)