【发布时间】:2017-01-21 02:10:46
【问题描述】:
我在序列化/反序列化时堆栈中的元素顺序被颠倒时遇到问题。请参阅此演示以进行复制:
using System;
using System.Collections.Generic;
using Newtonsoft.Json;
namespace StackChecker
{
class Program
{
enum Screen
{
Unknown,
Bypass,
ClaimDetails,
ClaimSearch,
ClaimSearchResults,
PatientSearchResults
}
static void Main(string[] args)
{
var screens = new Stack<Screen>();
screens.Push(Screen.Unknown);
screens.Push(Screen.Bypass);
screens.Push(Screen.ClaimDetails);
screens.Push(Screen.ClaimSearch);
screens.Push(Screen.ClaimSearchResults);
screens.Push(Screen.PatientSearchResults);
foreach (var screen in screens)
{
Console.WriteLine("Screen {0}: {1}", (int)screen, screen);
}
var screenJson = JsonConvert.SerializeObject(screens);
Console.WriteLine("Screens Json: \"{0}\"", screenJson);
var screens2 = JsonConvert.DeserializeObject<Stack<Screen>>(screenJson);
foreach (var screen in screens2)
{
Console.WriteLine("Screen {0}: {1}", (int)screen, screen);
}
var screenJson2 = JsonConvert.SerializeObject(screens2);
Console.WriteLine("Screens Json: \"{0}\"", screenJson2);
Console.ReadLine();
}
}
}
这会输出以下内容:
Screen 5: PatientSearchResults
Screen 4: ClaimSearchResults
Screen 3: ClaimSearch
Screen 2: ClaimDetails
Screen 1: Bypass
Screen 0: Unknown
Screens Json: "[5,4,3,2,1,0]"
Screen 0: Unknown
Screen 1: Bypass
Screen 2: ClaimDetails
Screen 3: ClaimSearch
Screen 4: ClaimSearchResults
Screen 5: PatientSearchResults
Screens Json: "[0,1,2,3,4,5]"
所以,问题是 - 为什么顺序颠倒了? (我也用数组试过这个,可以证明数组元素没有反转)
这可以避免吗?
如果没有,有人想出一个优雅的解决方法吗?
【问题讨论】:
-
序列化不是这里的问题。如果您编写以下代码
var s1=new Stack<int>(new[]{0,1,2,3,4});var s2=new Stack<int>(s1);,您将看到相同的问题,它源于在提供IEnumerable参数时如何编写Stack构造函数。使固定?在构造堆栈之前反序列化为列表并反转? -
Stack<T>的默认枚举器按照它们从堆栈中弹出的顺序枚举项目。如果您按该顺序将项目推送到另一个堆栈,则另一个堆栈将以相反的顺序包含项目。