我该如何将此源更改为LINQ

List<Node> resultList = new List<Node>();
NodeEqualityComparer comparer = new NodeEqualityComparer();
foreach (Vector3 move in moveList)
{
    foreach (Node sight in sightList)
    {
        if (comparer.Equals((Vector3)sight.position, move))
            resultList.Add(sight);
    }
}

var resultList = moveList.SelectMany(m => sightList.Where( s => comparer
                                       .Equals((Vector3)s.position, m)).ToList();

这是更有效的，因为您想要一种join:

List<Node> resultList = moveList
    .Join(sightList, m => m, s => (Vector3)s.position, (m, s) => s, comparer)
    .ToList();

我不确定你是否真的必须将其更改为LINQ版本…

List<Node> resultList;
NodeEqualityComparer comparer = new NodeEqualityComparer();
resultList = (from m in moveList
             from s in sightList
             where comparer.Equals((Vector3)s.position, m)
             select s).ToList();