Question

I want to have 2 models in one view. The page contains both LoginViewModel and RegisterViewModel.

e.g.

public class LoginViewModel
{
    public string Email { get; set; }
    public string Password { get; set; }
}

public class RegisterViewModel
{
    public string Name { get; set; }
    public string Email { get; set; }
    public string Password { get; set; }
}

Do I need to make another ViewModel which holds these 2 ViewModels?

public BigViewModel
{
    public LoginViewModel LoginViewModel{get; set;}
    public RegisterViewModel RegisterViewModel {get; set;}
}

I need the validation attributes to be brought forward to the view. This is why I need the ViewModels.

Isn’t there another way such as (without the BigViewModel):

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

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

Answer 1

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