枚举在C#中表现异常
本文关键字：异常 枚举 | 更新日期: 2023-09-27 18:21:39
我正在为一个学校项目编程（实现搜索算法），遇到了以下问题：
有一个名为action的变量，其类型为enum Actions｛esquerda=0，abaixo=1，direita=2，acima=3｝。在其中一个搜索算法扩展给定状态的邻居（名为Neighbours的属性执行该过程）后，它调用一个方法（Expansion（）），该方法获取可能的邻居并以列表形式返回。问题是在返回之后，如果不做任何事情，变量action的值在调试模式下第一次读取后会发生异常变化。
行：List temp=Expansion（）；在调用并填充变量temp之后，当您第二次读取temp列表中任何元素的value操作时，它会将其值更改为枚举（acima）的最后一项。
public class PuzzleState : Search.Node
{
private States[,] actualState;
private int empLinePos;
private int empColumPos;
private int dimension;
private Actions action;
private PuzzleState father;
private List<PuzzleState> children = new List<PuzzleState>();
public IEnumerable<Search.Node> Neighbours
{
get
{
List<PuzzleState> temp = Expansion();
// List<Search.Node> converted = Convert(temp);
return null;
}
}
public PuzzleState(int dimension, States[,] iniStates, Actions lastAction, PuzzleState father)
{
actualState = new States[dimension, dimension];
actualState = iniStates;
this.action = lastAction;
this.dimension = dimension;
this.father = father;
for (int i = 0; i < dimension; i++)
{
for (int j = 0; j < dimension; j++)
{
if (actualState[i, j] == States.Empty)
{
empLinePos = i;
empColumPos = j;
return;
}
}
}
}
public List<PuzzleState> Expansion()
{
List<PuzzleState> suns = new List<PuzzleState>();
foreach (Actions item in System.Enum.GetValues(typeof(Actions)))
{
PuzzleState temp = SucessorFunc(item);
if (temp != null)
{
suns.Add(temp);
}
}
return suns;
}
public PuzzleState SucessorFunc(Actions action)
{
this.action = action;
switch (action)
{
case Actions.esquerda:
if (empColumPos > 0)
{
States[,] newPossibilities = Copy();
newPossibilities[empLinePos, empColumPos] = newPossibilities[empLinePos, empColumPos - 1];
newPossibilities[empLinePos, empColumPos - 1] = States.Empty;
return new PuzzleState(dimension, newPossibilities, action, this);
}
break;
case Actions.direita:
if (empColumPos < dimension - 1)
{
States[,] newPossibilities = Copy();
newPossibilities[empLinePos, empColumPos] = newPossibilities[empLinePos, empColumPos + 1];
newPossibilities[empLinePos, empColumPos + 1] = States.Empty;
return new PuzzleState(dimension, newPossibilities, action, this);
}
break;
case Actions.acima:
if (empLinePos > 0)
{
States[,] newPossibilities = Copy();
newPossibilities[empLinePos, empColumPos] = newPossibilities[empLinePos - 1, empColumPos];
newPossibilities[empLinePos - 1, empColumPos] = States.Empty;
return new PuzzleState(dimension, newPossibilities, action, this);
}
break;
case Actions.abaixo:
if (empLinePos < dimension - 1)
{
States[,] newPossibilities = Copy();
newPossibilities[empLinePos, empColumPos] = newPossibilities[empLinePos + 1, empColumPos];
newPossibilities[empLinePos + 1, empColumPos] = States.Empty;
return new PuzzleState(dimension, newPossibilities, action, this);
}
break;
}
return null;
}
}
正如我所知，这听起来很疯狂，我制作了一个视频来展示这种新的C#效果：
http://youtu.be/gXQ6QyhMDDI
代码只是一个.cs文件，链接在这里。
https://www.dropbox.com/sh/gc80ld47eps08nr/AAA3v-t-Jcv_-5CeDzxriLKua?dl=0
如果有人想看看，告诉我这里到底发生了什么，我将不胜感激。
谢谢。
解决方案：
我找到了一种方法，添加了一个名为actionName的字符串var。每次我创建一个新的PuzzleState时，我都会将其值设置为action.tostring（）。但我仍然不知道为什么操作值会继续更改最后一个项的枚举值。
构造函数中包含actionName变量及其集合的新代码：
public class PuzzleState : Search.Node
{
private States[,] actualState;
private int empLinePos;
private int empColumPos;
private int dimension;
private Actions action;
private string actionName;
private PuzzleState father;
private List<PuzzleState> children = new List<PuzzleState>();
public IEnumerable<Search.Node> Neighbours
{
get
{
List<PuzzleState> temp = Expansion();
// List<Search.Node> converted = Convert(temp);
return null;
}
}
public PuzzleState(int dimension, States[,] iniStates, Actions lastAction, PuzzleState father)
{
actualState = new States[dimension, dimension];
actualState = iniStates;
this.actionName = lastAction.ToString();
this.action = lastAction;
this.dimension = dimension;
this.father = father;
for (int i = 0; i < dimension; i++)
{
for (int j = 0; j < dimension; j++)
{
if (actualState[i, j] == States.Empty)
{
empLinePos = i;
empColumPos = j;
return;
}
}
}
}
public List<PuzzleState> Expansion()
{
List<PuzzleState> suns = new List<PuzzleState>();
foreach (Actions item in System.Enum.GetValues(typeof(Actions)))
{
PuzzleState temp = SucessorFunc(item);
if (temp != null)
{
suns.Add(temp);
}
}
return suns;
}
public PuzzleState SucessorFunc(Actions action)
{
this.action = action;
switch (action)
{
case Actions.esquerda:
if (empColumPos > 0)
{
States[,] newPossibilities = Copy();
newPossibilities[empLinePos, empColumPos] = newPossibilities[empLinePos, empColumPos - 1];
newPossibilities[empLinePos, empColumPos - 1] = States.Empty;
return new PuzzleState(dimension, newPossibilities, action, this);
}
break;
case Actions.direita:
if (empColumPos < dimension - 1)
{
States[,] newPossibilities = Copy();
newPossibilities[empLinePos, empColumPos] = newPossibilities[empLinePos, empColumPos + 1];
newPossibilities[empLinePos, empColumPos + 1] = States.Empty;
return new PuzzleState(dimension, newPossibilities, action, this);
}
break;
case Actions.acima:
if (empLinePos > 0)
{
States[,] newPossibilities = Copy();
newPossibilities[empLinePos, empColumPos] = newPossibilities[empLinePos - 1, empColumPos];
newPossibilities[empLinePos - 1, empColumPos] = States.Empty;
return new PuzzleState(dimension, newPossibilities, action, this);
}
break;
case Actions.abaixo:
if (empLinePos < dimension - 1)
{
States[,] newPossibilities = Copy();
newPossibilities[empLinePos, empColumPos] = newPossibilities[empLinePos + 1, empColumPos];
newPossibilities[empLinePos + 1, empColumPos] = States.Empty;
return new PuzzleState(dimension, newPossibilities, action, this);
}
break;
}
return null;
}
}
在SuccessorFunc中，您正在设置action成员变量：
this.action = action;
因此，当Expansion方法循环时，它将被设置为每个枚举值。