Question

is it possible to recursively filter all items in recursive tree with linq to objects.

This is the model i am using. This is given to me by another application

public class Menu
{
   public string Name{get;set;}
   public string Roles{get;set;}
   public List<Menu> Children{get;set;}
}

When the user logs into my application i need to check the users roles against the roles specified in for the menu item. I know i can write a recursive method that check this using a for loop.

I there anyway to get this using like ‘MenuList.Where(..check the roles)

thanks in advance

Answer 1

I’d just implement another method in the Menu class:

public class Menu
{
    public string Name { get; set; }
    public string Roles { get; set; }
    public List<Menu> Children { get; set; }
    /// <summary>
    /// Checks whether this object or any of its children are in the specified role
    /// </summary>        
    public bool InRole(string role)
    {
        if (role == null)
        {
            throw new ArgumentNullException("role");
        }
        var inRole = (this.Roles ?? String.Empty).Contains(role);
        if (!inRole & Children != null)
        {
            return Children.Any(child => child.InRole(role));
        }
        return inRole;
    }
}

And then you can just write LINQ queries like:

var inRole = menuList.Where(menu => menu.InRole("admin"));

It will work recursively.