c# - 如何合并两个列表而不重复？ (可能的二人组)

Question

以为我的搜索选项范围很容易找到这个。

我希望合并两个列表而不重复。这是我的破解尝试。

public class MyClass
{
    public Guid? MyGuid { get; set; }
}

//.....

Guid? dupGuid1 = Guid.NewGuid();
Guid? uniqueGuid1 = Guid.NewGuid();

MyClass x1 = new MyClass { MyGuid = dupGuid1 };
List<MyClass> myMainList = new List<MyClass>() { x1 };


MyClass y1 = new MyClass { MyGuid = dupGuid1 };
MyClass y2 = new MyClass { MyGuid = uniqueGuid1 };
List<MyClass> myAddList = new List<MyClass> { y1, y2 };

myMainList.AddRange(myAddList
   .Where(w => w.MyGuid != myAddList.SelectMany(s => s.MyGuid).ToList()));

Debug.Assert(myMainList.Count == 2);

我该怎么做？谢谢。

Answer 1

var uniqueList = myMainList
   .Concat(myAddList)
   .GroupBy(item => item.MyGuid)
   .Select(group => group.First())
   .ToArray();

或

  var uniqueList = myMainList
      .Concat(myAddList)
      .DistinctBy(item => item.MyGuid)
      .ToArray();

  public static IEnumerable<T> DistinctBy<T, TKey>(this IEnumerable<T> items, 
                    Func<T, TKey> keyer)
  {
    var set = new HashSet<TKey>();
    var list = new List<T>();
    foreach (var item in items)
    {
      var key = keyer(item);
      if (set.Contains(key))
        continue;
      list.Add(item);
      set.Add(key);
    }
    return list;
  }