C# Linq Intersect

Question

Most of the time I just use foreach statements, because that is a lot easier for me to code. Later on, when my code is done, I convert the foreach into LINQ statements where it makes sense.

I want to learn how to write good readable LINQ statements. How would you guys convert this foreach code into a correct LINQ statement ?

private List<QARoles> GetUserRoles(User user)
{
    //TODO: Fix this with LINQ intersect.

    var result = new List<QARoles>();
    foreach (var role in user.Roles)
    {
        foreach (QARoles qarole in System.Enum.GetValues(typeof(QARoles)))
        {
            if (role.Name.Equals(qarole.ToString()))
            {                        
                result.Add(qarole);
            }                    
        }
    }
    return result;
}

Answer 1

This can be simplified to:

var result = user.Roles
                 .Where(r => Enum.IsDefined(typeof(QARoles), r.Name))
                 .Select(r => (QARoles)Enum.Parse(typeof(QARoles), r.Name))
                 .ToList();