asp.net mvc - Dropdownlistfor returns null value -

i have customer class property gender. created list of gender type contains , id number , gender type. when form submitted, getting null value.

view

@model movierentals.viewmodel.customerview <div class="form-group">     <h4>@html.labelfor(l => l.customer.birthdate)</h4>     @html.dropdownlistfor(l => l.customergender, new selectlist(model.customergender, "genderid", "gendertype"), "select gender", new { @class = "form-control" }) </div> 

model

public class customerview {     public ienumerable<membershiptype> membershiptypes{ get; set; }     public customer customer { get; set; }     public list<genderclass> customergender{ get; set; } }  public class genderclass {     public int genderid { get; set; }     public string gendertype { get; set; } } 

controller

public actionresult new()     {         var membershipty = _context.memebershiptype.tolist();         var viewmodel = new customerview();         viewmodel.customergender = new list<genderclass>()         {             new genderclass(){ genderid = 1, gendertype = "male"},             new genderclass() { genderid = 2, gendertype = "female"}         };         viewmodel.membershiptypes = membershipty;         return view(viewmodel);     } 

you need 2 properties: 1 hold selected value , 1 hold options. 1 holds options should ienumerable<selectlistitem>. genderclass class superfluous.

also, using integer id value doesn't make sense when meaning of value not obvious. here, fact 1 means male exists in new action. anywhere else, have repeat logic (which introduces opportunities errors, e.g. male 1 or 0). further, if decide change values, must remember change them everywhere. if want use integer id, should abstract away meaning somewhere, enum, static class, database table, etc. far better choice keep string, , use dropdown merely enforce normalization of string value.

public string customergender { get; set; }  public ienumerable<selectlistitem> customergenderchoices {         {         return new list<selectlistitem>         {             new selectlistitem { value = "male", text = "male" },             new selectlistitem { value = "female", text = "female" }         }     } } 

then, in view:

@html.dropdownlistfor(m => m.customergender, model.customergenderchoices, "select gender", new { @class = "form-control" }) 

alternatively, if use enum:

public enum genders {     male = 1,     female = 2 } 

then, in view model, need 1 property, store value:

public genders customergender { get; set; } 

then, in view, can make use of enumdropdownlistfor:

@html.enumdropdownlistfor(m => m.customergender, "select gender", new { @class = "form-control" }) 

as enum, value stored int, benefit here have strongly-typed association between integer values , mean. example, rather doing like:

if (customer.customergender == 1) // male 

you can do:

if (customer.customergender == genders.male) 

obviously, second version more obvious in meaning.