C# 需要通过与'比较来筛选“dataBefore”的数据；dataAfter'；

我有两个列表，需要在

dataAfter

列表中筛选

Name

和

SectionId

不匹配的

dataBefore

中的数据

var dataBefore = new List<School>
        {
            new School { Name = "N1", SectionId = null },
            new School { Name = "N2", SectionId = new Guid("6aba7a38-8e61-472d-b4ce-b9fc2011af3f") },
            new School { Name = "N3", SectionId = null },
            new School { Name = "N4", SectionId = new Guid("ca663d45-04b8-4c80-96b6-c3760352a6ac") }
        };

        var dataAfter = new List<School>
        {
            new School { Name = "N1", SectionId = new Guid("5be0fc99-4826-4fbf-a190-b930af730b93") },
            new School { Name = "N3", SectionId = null },
            new School { Name = "N4", SectionId = null }
        };

下面的查询给出了完全相反的结果（仅

N3

），如何获得高于预期的结果

 var x = dataBefore.Where(y => dataAfter.Any(z => z.Name == y.Name && z.SectionId == y.SectionId)).ToList();

如果Any（）返回false，则可以得到结果

 var x = dataBefore.Where(y => dataAfter.Any(z => z.Name == y.Name && z.SectionId == y.SectionId)).ToList();

var x = dataBefore.Where(y => !dataAfter.Any(z => z.Name == y.Name && z.SectionId == y.SectionId)).ToList();