Question

我有以下两个清单：

var firstList = new List<ProgramInfo> ()
{
    new ProgramInfo {Name = "A", ProgramId = 1, Description = "some text1"},
    new ProgramInfo {Name = "C", ProgramId = 2, Description = "some text2"},
    new ProgramInfo {Name = "D", ProgramId = 3, Description = "some text3"},
    new ProgramInfo {Name = "E", ProgramId = 4, Description = "some text4"}
};

var secondList = new List<ProgramInfo> ()
{
    new ProgramInfo {Name = "C", ProgramId = 2, Description = "some text1"},
    new ProgramInfo {Name = "D", ProgramId = 3, Description = "some text2"},
};

这两个列表是在运行时生成的，我必须根据这个列表中的程序ID选择常见的ProgramInfo

例如，在上述示例的情况下，输出应为

var thirdList = new List<ProgramInfo>()
{
    new ProgramInfo {Name = "C", ProgramId = 2, Description = "some text1"},
    new ProgramInfo {Name = "D", ProgramId = 3, Description = "some text2"},
};

  public class ProgramInfo
  {
    public string Name { get; set; }
    public int ProgramId { get; set; }
    public string Description { get; set; }
  }

有人可以建议我怎样才能使用lambda表达式？

Answer 1

使用Linq .Intersect。为了实现这一目标，您的课程需要覆盖Equals和GetHashCode

var thirdList = firstList.Intersect(secondList);

您也可以指定IEqualityComparer而不是覆盖这些功能：

public class Comparer : IEqualityComparer<ProgramInfo>
{
   public bool Equals(ProgramInfo x, ProgramInfo y)
   {
      return x.Name == y.Name &&
             x.ProgramId == y.ProgramId &&
             x.Description == y.Description;
   }

   public int GetHashCode(ProgramInfo obj)
   {
      return obj.Name.GetHashCode() ^
             obj.ProgramId.GetHashCode() ^
             obj.Description.GetHashCode();
   }
}

var thirdList = firstList.Intersect(secondList, new Comparer());

使用lambda表达式

1 个答案: