检索其中一个项目存在于一个项目列表中的项目列表

Question

Please excuse the slightly confusing title. I have a model (Project) which contains a list of items (Users).

I would like to retrieve all of the projects, where the current user is a member of the user list for that project.

I've tried:

List<Project> _MemberProjects =
                    _Db.Projects.Where(p =>
                         p.Users.Contains(_User)
                    ).ToList();

This results in the following error:

Unable to create a constant value of type 'Nimble.Models.UserAccount'. Only primitive types or enumeration types are supported in this context.

User Model:

public class UserAccount
{
    public int UserID { get; set; }
    public string Username { get; set; }
    public string Password { get; set; }
    public string Name { get; set; }
    public string Surname { get; set; }
    public string Email { get; set; }
    public ICollection<Project> Projects{....}
}

Project Model

public class Project
{
    public int ProjectID { get; set; }
    public DateTime CreatedDate { get; set; }
    public string ProjectName { get; set; }        
    public string Owner { get; set; }       
    public ICollection<UserAccount> Users{...}
    public ICollection<ProjectGroup> Groups{...}
}

Answer 1

Haven't tried this, but it might work:

List<Project> _MemberProjects =
                _Db.Projects.Where(p =>
                     p.Users.Any(u => u.UserID == _User.UserID )
                ).ToList();

Answer 2

The problem is that you are mixing together Linq (the WHERE clause) and a non-Linq Collection operation (Contains). Try using pure Linq. @JamesBond's answer might work.

Are you querying a database? Then a JOIN might be another solution, but the exact syntax depends on how you are storing the relationship between the two tables.