c# - 为什么 Assert.AreEqual(T obj1, Tobj2) 会因相同的对象而失败

Question

我有一个包含多个结构的类:

public class NavigationMenu
{
    public struct NavigationMenuItem
    {
        public bool Enabled { get; set; }
        public int NumberOfPendingOperations { get; set; }
    }

    public NavigationMenuItem SubmitExpenses { get; set; }
    public NavigationMenuItem ManageExpenses { get; set; }
    public NavigationMenuItem SubmitBudgets { get; set; }
    public NavigationMenuItem ManageBudgets { get; set; }
    public NavigationMenuItem AuthorizeExpenses { get; set; }
    public NavigationMenuItem ApproveExpenses { get; set; }
    public NavigationMenuItem PayExpenses { get; set; }
    public NavigationMenuItem BillExpenses { get; set; }
    public NavigationMenuItem ManageReturnedExpenses { get; set; }
    public NavigationMenuItem ManageIncompleteExpenses { get; set; }
    public NavigationMenuItem ManageOrders { get; set; }
    public NavigationMenuItem ApproveBudgets { get; set; }
    public NavigationMenuItem AdministrateSystem { get; set; }
}

在单元测试中，我调用函数并比较结果:

NavigationMenu expected = new NavigationMenu();
        expected.SubmitExpenses = new NavigationMenu.NavigationMenuItem { Enabled = true };
        expected.ManageExpenses = new NavigationMenu.NavigationMenuItem { Enabled = true };

        NavigationMenu actual = HomeControllerHelper.GetNavigationMenuByUserRole(userRole);

        Assert.AreEqual(expected, actual);

但是 Assert.AreEqual 总是抛出 AssertFailedException。对象是相同的，我已经使用调试器验证了这一点。请分享任何想法。谢谢。

Answer 1

Assert.AreEqual(expected, expected) 调用不应失败。如果您在问题中犯了错误并且您的意思是 Assert.AreEqual(expected, actual) 并且您的 HomeControllerHelper.GetNavigationMenuByUserRole 返回了 NavigationMenu 的新实例，那么对 Assert.AreEqual 的调用总是会失败，原因您的类型 NavigationMenu 是一个类，因此是一个引用类型，即使您将实例的属性设置为相同的值也是如此。

如果两个变量指向相同的引用(也称为 ReferenceEqual)而不是如果两个引用包含相同的(属性)值，则 Assert.AreEqual 执行相等性检查。

如果您的类的两个实例相等，您可以覆盖 NavigationMenu 类的 Equals 方法以提供自定义实现。