OrderBy异常“至少一个对象必须实现IComparable". [英] OrderBy exception "At least one object must implement IComparable"

问题描述

我正在尝试对列表进行排序.

I'm trying to sort a list.

此行引发异常:;

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

但是，这可行:

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

我该如何解决?

推荐答案

让我们看一下:

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

我们要订购的东西是:

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

这就是说；对于每个o项，请按序列进行排序，并按距离o.Rows[0].Elements.OrderBy(e => e.Distance)进行排序.那没有多大意义.您如何比较两个序列，例如{1,3,4}和{1,8}?

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} ?

但是，您可以采用 first 距离，或 min / max 距离:

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();

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