c# - Mvc - Form with viewmodel -

im working in mvc , have form in view receive viewmodel selectlist insert values dropdownlist.

but on submit form nothing work , can´t figured out going on.

on submit form null database.

someone can me out pls?

here code: view:

model myproject.models.viewmodel @using(html.beginform()) {     @html.dropdownlistfor(o => o.cp.companylist,model.cp.companylist)      @html.editorfor(o => o.md.title)      @html.editorfor(o => o.md.edition)     @html.editorfor(o => o.md.number)    <input type="submit" name="submit" value="add new"> } 

controller:

  public actionresult create()         {   viewmodel vm = new viewmodel ();             return view(vm);         }          //         // post: create          [httppost]         public actionresult create(mydata model)         {             if (modelstate.isvalid)             {                 db.res.add(model);                 db.savechanges();                 return redirecttoaction("index","adminpanel");             }              return view(model);         } 

model:

 public class viewmodel     {         public mydata md { get; set; }         public company cp { get; set; }     } 

mydata - model:

 public class mydata     {         public int id { get; set; }         public string company_name{ get; set; }         public string title{ get; set; }         public string edition{ get; set; }         public string number{ get; set; }     } public class defaultconnection : dbcontext     {         public dbset<mydata> res{ get; set; }     } 

companies - model:

 public class company     {         public int id { get; set; }         public string name{ get; set; }         public selectlist companylist{ get; set; }            public company()         {             companylist= getcompanies();         }          public selectlist getcompanies()         {             var list = new list<selectlistitem>();             string connection = configurationmanager.connectionstrings["defaultconnection"].connectionstring;              using (var con = new sqlconnection(connection))             {                 con.open();                 using (var command = new sqlcommand("select * mycompanies", con))                 {                     sqldatareader reader = command.executereader();                     while (reader.read())                     {                         //string id = reader[0] string;                         string name_company= reader[1] string;                         list.add(new selectlistitem() { text = name_company, value = name_company});                     }                 }                 con.close();             }             return new selectlist(list, "value", "text");         } } 

the problem you're creating viewmodel, it's md , cp properties not initialized. why when you're calling o.cp.companylist in view, o.cp null.

since you're trying create() don't want assign existing data mydata or company, have make sure properties initialized. can in viewmodel constructor:

public class viewmodel {     public viewmodel()     {          this.md = new mydata();          this.cp = new company();     }      public mydata md { get; set; }     public company cp { get; set; } }