How to filter IEnumerable based on an entity input parameter

Question

I\'m using now Entity framework- but it\'s a problem \"shared\" between all ORM\'s and even IEnumerable.

Let\'s say I have a method in MVC looks like this:

Answer 1

Try that. This is using reflection and expressions to build the query dynamically. I tested it only with objects.

static IQueryable Filter(IQueryable col, T filter)
{
    foreach (var pi in typeof(T).GetProperties())
    {
        if (pi.GetValue(filter) != null)
        {
            var param = Expression.Parameter(typeof(T), "t");
            var body = Expression.Equal(
                Expression.PropertyOrField(param, pi.Name),
                Expression.PropertyOrField(Expression.Constant(filter), pi.Name));
            var lambda = Expression.Lambda>(body, param);
            col = col.Where(lambda);
        }
    }

    return col;
}