filter linq query based on role of logged in user MVC3 Controller

Question

What I am trying to do is filter a query based on the role of the logged in user in my MVC3 Controller. I am restricting users to have only one role; no user can have more than one role. I have some code snippets but I am not sure this is the way to go. And also if someone can assist me to achieve my goal

  string[] roles = Roles.GetRolesForUser();

    string color= roles[0];

    string vcolor = color.Substring(0, 4);

    switch (vcolor)
                {
                    case "Rewa":
                        vcolor = "white";
                        break;
                    case "Ukau":
                        vcolor == "black";
                        break;
                    case "Whau":
                        vcolor = "green";
                        break;
                    case "Angi":
                        vcolor = "Blue";
                        break;
                }

public ActionResult _MembersView()
    {
        var pagenew = db.Members

            .Where(u => u.color == vcolor)(I will want to then set this condition to the vcolor dynamically)
            .OrderBy(u => u.Tcd);
            //.Take(12);
        return PartialView(pagenew);

    }

Answer 1

Well put your logic into a method:

private string GetVColorForCurrentUser()
{
    string[] roles = Roles.GetRolesForUser();
    string color = roles[0];
    string vcolor = color.Substring(0, 4);
    switch (vcolor)
    {
        case "Rewa":
            return "white";
        case "Ukau":
            return "black";
        case "Whau":
            return "green";
        case "Angi":
            return "Blue";
    }
    return vcolor;
} 

and then call this method:

public ActionResult _MembersView()
{
    var pagenew = db
        .Members
        .Where(u => u.color == GetVColorForCurrentUser())
        .OrderBy(u => u.Tcd);
    return PartialView(pagenew);
}

Or directly write it as a filter method:

private bool CurrentUserHasSameVColor(Member member)
{
    string[] roles = Roles.GetRolesForUser();
    string color = roles[0];
    string vcolor = color.Substring(0, 4);
    switch (vcolor)
    {
        case "Rewa":
            vcolor = "white";
            break;
        case "Ukau":
            vcolor = "black";
            break;
        case "Whau":
            vcolor = "green";
            break;
        case "Angi":
            vcolor = "Blue";
            break;
    }
    return member.color == vcolor;
}

and then:

public ActionResult _MembersView()
{
    var pagenew = db
        .Members
        .Where(CurrentUserHasSameVColor)
        .OrderBy(u => u.Tcd);
    return PartialView(pagenew);

}