LINQ查询中的动态属性

Question

I'm trying to convert a complex domain model into a CSV format. However the dynamic structure of the model is pushing my LINQ wizardry to its limit :)

The desired result should look something like the following. A header row, then data rows. Note that some fields are empty and others have multiple.

Output

PropA;RolenameA;RolenameB;RolenameC
123;username1,username2;username1;username2
321;;;username1

I wish to create a LINQ query which dynamically can add properties for each Role and then fill that property with the correct username(s). I recognize that the header and the data must be in 2 different statements.

Pseudo code

var result = new { "PropA", Roles.ForEach(x => x.Rolename) }
result += query.Select(x => new { x.PropA, x.UserRoles.ForEach(...) });

Is what I'm trying to do not possible with LINQ and I should do it "manually" with a dynamic object, or is there some black magic I need to learn :)?

Model

public class A
{
    public int PropA { get; set; }
    public IEnumerable<UserRole> UserRoles { get; set; }
}

public class UserRole
{
    public Role Role { get; set; }
    public User User { get; set; }
}

public class Role
{
    public string Rolename { get; set; }
}

public class User
{
    public string Username { get; set; }
}

Answer 1

I ended up doing it "manually" with an ExpandoObject.

foreach (var item in items)
{
    var obj = new ExpandoObject() as IDictionary<string, Object>;
    obj.Add("PropA", item.PropA);

    foreach (var role in roles)
    {
        obj.Add(role.Name,
                String.Join(",", item.UserRole.Where(x => x.Role == role).Select(x => x.User.Name)));
    }
    // omitted...
}