Question

I’m trying to sort a list.

This line throws the exception: ;

List<DistanceInfo> ListedDuration = 
              Distances.OrderBy(o => o.Rows[0].Elements.OrderBy(e => e.Distance))
                       .ToList();

But, this works:

List<DistanceInfo> ListedDuration = 
              Distances.OrderBy(o => o.Rows[0].Elements[0].Distance)
                       .ToList();

How can I fix this ?

Answer 1

Let’s look at:

List<DistanceInfo> ListedDuration = Distances.OrderBy(
    o => o.Rows[0].Elements.OrderBy(e => e.Distance)
).ToList();

The thing we are ordering by is:

o => o.Rows[0].Elements.OrderBy(e => e.Distance)

which is to say; for each item o, order it by the sequence ordered by distance o.Rows[0].Elements.OrderBy(e => e.Distance). That doesn’t make much sense. How do you compare two sequences, such as {1,3,4} to {1,8} ?

You might, however, take the first distance, or the min / max distance:

List<DistanceInfo> ListedDuration = Distances.OrderBy(
    o => o.Rows[0].Elements[0].Distance
).ToList();

List<DistanceInfo> ListedDuration = Distances.OrderBy(
    o => o.Rows[0].Elements.Min(e => e.Distance)
).ToList();

List<DistanceInfo> ListedDuration = Distances.OrderBy(
    o => o.Rows[0].Elements.Max(e => e.Distance)
).ToList();