ASP.NET MVC Complex Model Validation

I have a complex Model

public class ComplexModel
{

    public UserModel userModel;

    public ExtraInfoModel extraModel;
}

where

UserModel may have required fields

as in:

public class UserModel
{

     [Required]
     public string email;
}

how do I validate ComplexModel to make sure that the data annotations on its member models are being taken into the account in ComplexModel validation?

Thank you.

UPDATE:

Here's my exact scenario. When I call ModelState.IsValid in a controller action on ManageProfileModel regardless of whether "SelectedValue" of ListModelRequired member of GeneralInfoModel was set or not the model state is valid.

public class ManageProfileModel
{
    [Required(ErrorMessage="Experience is required")]
    public int LevelOfExperienceTypeID { get; set; }
    public GeneralInfoModel GeneralInfoModel { get; set; }
}

public class GeneralInfoModel
{
    [Required]
    [DisplayName("Profile Headline")]
    public string ProfileName { get; set; }

    [DisplayName("Signature")]
    public string Signature { get; set; }

    [Required]
    public ListModelRequired LevelOfExperience { get; set; }
}

public class ListModel
{
    public ListModel()
    {
    }

    public ListModel(string name)
    {
        this.Name = name;
    }

    public ListModel(string name, string selectedValue):this(name)
    {
        this.SelectedValue = selectedValue;
    }

    public ListModel(string name, IEnumerable<SelectListItem> members):this(name)
    {
        this.Members = members;
    }

    public ListModel(string name, IEnumerable<Se开发者_开发问答lectListItem> members, string selectedValue)
        : this(name, members)
    {
        this.SelectedValue = selectedValue;
    }

    public IEnumerable<SelectListItem> Members { get; set; }

    public string Name { get; set; }

    public virtual string SelectedValue { get; set; }

    public string Label { get; set; }
}

public class ListModelRequired : ListModel
{
    [Required]
    public override string SelectedValue { get; set; }

    public ListModelRequired():base()
    {
    }

    public ListModelRequired(string name):base(name)
    {
    }

    public ListModelRequired(string name, string selectedValue):base(name,selectedValue)
    {
    }

    public ListModelRequired(string name, IEnumerable<SelectListItem> members)
        : base(name, members)
    {
    }

    public ListModelRequired(string name, IEnumerable<SelectListItem> members, string selectedValue)
        : base(name, members,selectedValue)
    {
    }
}

---

I think that the default model binder gets this right, validating submodels that use the data annotations. What problem are you actually having it with it? For example, I have something similar to:

public class OnlineDonationModel
{
     [Required]
     public decimal? Amount { get; set; }

     public ContactModel Contact { get; set; }
}

public class ContactModel
{
     [Required]
     public string FirstName { get; set; }

     [Required]
     public string LastName { get; set; }

     [Required]
     public string Address { get; set; }

     ...
}