Multiple models in a view

There are lots of ways…

1. with your BigViewModel
   you do:

   @model BigViewModel    
   @using(Html.BeginForm()) {
       @Html.EditorFor(o => o.LoginViewModel.Email)
       ...
   }
   

2. you can create 2 additional views

   Login.cshtml

   @model ViewModel.LoginViewModel
   @using (Html.BeginForm("Login", "Auth", FormMethod.Post))
   {
       @Html.TextBoxFor(model => model.Email)
       @Html.PasswordFor(model => model.Password)
   }
   

   and register.cshtml same thing

   after creation you have to render them in the main view and pass them the viewmodel/viewdata

   so it could be like this:

   @{Html.RenderPartial("login", ViewBag.Login);}
   @{Html.RenderPartial("register", ViewBag.Register);}
   

   or

   @{Html.RenderPartial("login", Model.LoginViewModel)}
   @{Html.RenderPartial("register", Model.RegisterViewModel)}
   

3. using ajax parts of your web-site become more independent

4. iframes, but probably this is not the case