在EntityFramework中，如何搜索可能为null但可能不为null的属性

Question

我正在尝试找到一个适用于下面查询的语句。 我可以使用相同的代码查询空值或整数值，但不能同时查询两者。

  int? age = null;

  Student student;

  age = 12;

  //works
  student = entities.Students.Single(s => s.Age == age);

  //does not work - crash
  student = entities.Students.Single(s => s.Age.Equals(age));

  age = null;
  //works
  student = entities.Students.Single(s => s.Age.Equals(age));

请注意第一个答案：

//crashes with error - sequence contains no elements
age = null;
student = entities.Students.Single(s => s.Age == age);

Answer 1

不幸的是，这是well known and reported issue。解决方法是：

student = entities.Students.Single(s => age == null ? s.Age == null : s.Age == age);

Answer 2

student = entities.Students.Single(s => s.Age == age);

那个应该满足你的要求，检查空值的相等性和值本身。