How to build memberexpression of memberexpression?

Question

Below are my classes:

public class A
{
    public int i { get; set; }
}

public class B
{
    public A a { get; set; }
    public int j { get; set; }
}

If I want to use expression to express bj>3 , I can do it like this:

ParameterExpression parameter = Expression.Parameter(typeof(B), "b");
MemberExpression member = Expression.PropertyOrField(parameter, "j");            
ConstantExpression constant = Expression.Constant(3);
return Expression.Lambda<Func<B, bool>>(Expression.GreaterThan(member, constant), parameter);

Now, how can I build an expression for bai>3 ?

Answer 1

Just create another MemberExpression based on the previous one:

ParameterExpression parameter = Expression.Parameter(typeof(B), "b");
MemberExpression memberA = Expression.PropertyOrField(parameter, "a");

// Use the previous MemberExpression here:
MemberExpression memberI = Expression.PropertyOrField(memberA, "i");

ConstantExpression constant = Expression.Constant(3);
return Expression.Lambda<Func<B, bool>>(Expression.GreaterThan(memberI, constant), parameter);