Use string instead. In Expression, compare(a, b)

I was trying to do similar as a lambda where clause (LINQ to SQL), and since various searches landed me on this page, so I'll share such a solution here in case it helps others who land here.

It is easiest when you simplify what you are doing with a generic expression of the Compare.

    public static Expression CompareLessThanOrEqualTo(Expression e1, Expression e2)
    {
        var compare = Expression.Call(typeof(string),
                           "Compare",
                           null,
                           new[] { e1, e2 });

        return Expression.LessThanOrEqual(compare, Expression.Constant(0));
    }

Then you use can this expression just like any other

    public static Expression<Func<TypeOfParent, bool>> PropertyLessThanOrEqualString<TypeOfParent, String>(PropertyInfo property, String value)
    {
        var parent = Expression.Parameter(typeof(TypeOfParent));
        var expressionBody = CompareLessThanOrEqualTo(Expression.Property(parent, property), Expression.Constant(value));
        return Expression.Lambda<Func<TypeOfParent, bool>>(expressionBody, parent);
    }

Witch can be used such as

public static IQueryable<T> ApplyFilters<T>(this IQueryable<T> query, List<GridFilters> gridFilters)
{
    // foreach filter
        // Get property (propertyInfo)
        // Get Value(s)
        // Apply Filter
        query = query.Where(PropertyLessThanOrEqualString<T, string>(propertyInfo, value1));

    // ...

    return query;
}

This is useful if you have a list of filters chosen by the user that you need to apply, where the values and operators can be both chosen. (Starts With, Contains, Between Range)