Join LINQ tables based on model definition

Question

I want to join tables using linq, based on the definition of the model. Example of what I want:

from department in User.departments...

My classes are:

USER CLASS:

public class User
{
    public User() {
        Departments = new List<Department>();
    }
    public int UserId { get; set; }
    public string UserName { get; set; }
    public virtual ICollection<Department> Departments { get; set; }
}

DEPARTMENT CLASS:

public class Department
{
    public int DepartmentId { get; set; }
    public string DepartmentName { get; set; }
    public virtual User User { get; set; }
}

I'm creating inside the user class this:

public bool hasDepartment(int DepartmentId, int UserId)
{
    var test = from department in User.departments
    //...
}

But I'm having this message: 'User' does not contain a definition for 'departments'.

I'm creating a ASP.NET MVC application. Am I doing anything wrong?

LINQ is correct, the User object does not have a definition for `departments`. It does, however, have one for `Departments` (notice the casing). I also agree with @Div, why virtual properties? Are you going to be overloading these somewhere else in some other subclasses? — Stephen P., Sep 28 '16 at 17:39
@Div most likely for lazy loading: http://stackoverflow.com/a/5599270/3330348 — PiotrWolkowski, Sep 28 '16 at 17:41
It's also not clear is `User` a class name or some collection reference in `hasDepartment` method. If it's the former, you should use `this` instead. — Gasper, Sep 28 '16 at 17:42
I've read the post about virtual and non virtual and I still don't get it. :/ — Richasantos, Sep 28 '16 at 17:47
@Richasantos I don't think it was directly related to your problem. I posted that as an answer to a question asked by Div — PiotrWolkowski, Sep 28 '16 at 18:02

score 1 · Answer 1 · answered Sep 28 '16 at 17:44

1

If the spelling of your message is exact then the reason for the error must be departments with lower d. Your 'Departments' property in the class definition is capital D.

answered Sep 28 '16 at 17:44

PiotrWolkowski

8,408
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score 1 · Accepted Answer · answered Sep 28 '16 at 18:01

User' does not contain a definition for 'departments'

Issue exist since Departments is not a static collection inside User class, so you need an object of User class to access the Departments ICollection property

Since in the User class, modify the access as follows:

var test = from department in Departments Or

`var test = from department in this.Departments`

Idea is same, to have object based access instead of static access

score 0 · Answer 3 · answered Sep 28 '16 at 18:00

0

public bool hasDepartment(int DepartmentId, int UserId)
{
    var test = from department in Departments
    ...
}

answered Sep 28 '16 at 18:00

Claudio Kazuo Hirakava

81
1
7

2

While this code may answer the question, providing additional context regarding why and/or how this code answers the question improves its long-term value. – ryanyuyu Sep 28 '16 at 20:52

Join LINQ tables based on model definition

3 Answers3