Question

我正在尝试显示保存在响应数据库中的部门，而没有学生分配到某个部门。我有以下代码，错误消息正确显示但没有学生的部门列表不是。

private static void displayDepartments(University u)
{
    foreach (Department d in u.Departments)
    {
          if (d.contains(null))
          {
              Console.WriteLine(d.ToString());
          }
          else
          {
              Console.WriteLine("All departments contain students");
          }
    }
}

Answer 1

这个答案基于澄清的问题（阅读其他答案的评论）。

bool errors = false;
foreach (Department d in u.Departments)
     if (d.students.Count == 0) // students is IList<> it has a property Count
     {
          Console.WriteLine(d.name); // name is string
          errors = true;
     }

if (!errors)
    Console.WriteLine("All departments contain students");

根据不准确的信息做出第一个答案：

由于您的Department类是IEnumerable，您将能够执行以下操作：

bool emptyDep = true;
foreach (Department d in u.Departments)
{
      if (!d.Any())
      {
          emptyDep = true;
          Console.WriteLine(d.ToString());
      }
}

if (!emptyDep)
{
    Console.WriteLine("All departments contain students")
}

Answer 2

这些方面应该有用......

private static void displayDepartments(University u)
{
    foreach (Department d in u.Departments)
    {
          if (d.students.Count == 0)
          {
          Console.WriteLine(d.name.ToString());
          }
          else
          {
          Console.WriteLine("All departments contain students");
          }
    }

}

如何显示没有测试数据的类？

2 个答案: