Using viewmodel in MVC to show data from multiple tables

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ASP.NET

ViewModel

MVC5

I have MVC framework User Table and my own Community Table. I also have a relationship CommunityUser table. I am virtually connecting CommunityUser table with community Table. Here is my Community class

public class Community
{
    [Key]
    public int CommunityID { get; set; }

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

    [Required]
    public string CommunityDomain { get; set; }
    public string CommunityAbout { get; set; }
    public string CommunityLogo { get; set; }

    public int PrivacyID { get; set; }

    public string CommunityAdmin { get; set; }
    public virtual PrivacyLevel PrivacyLevel { get; set; }
    public virtual  ICollection<CommunityUser> CommunityUsers { get; set; }

    public Community()
    {
        CommunityUsers = new Collection<CommunityUser>();
    }


}

I want to use User Table and Community User Table on my index page. I have created a ProfileDataViewModel having these two tables.

public class ProfileDataViewModel
{
    public ApplicationUser User { get; set; }
    public List<CommunityUser> CommunitiesList { get; set; }
}

Now when I am using this view model on my index function, it is throwing an exception. Here is my index function

public ActionResult Index()
    {
        var thisUser = db.Users.Where(u => u.UserName == User.Identity.Name).SingleOrDefault();

        var myDashboard = new ProfileDataViewModel()
        {
            User = thisUser,
            CommunitiesList = db.CommunityUsers.Include(x => x.Community).Where(u => u.UserID==thisUser.Id).ToList()

        };
        return View(myDashboard);
    }

What I have tried:

when I am using this view model on my index function, it is throwing an exception. Here is my index function