更新后的堆栈溢出异常.net 4.5

Question

有人可以帮帮我吗？我失去了理智：

以下代码在将.net更新为4.5.2

后给出了stackoverflowexception

private string CalculateStringOrder(Page p, string s)
{
    string res = null;
    char pad = '0';
    try
    {
        if (!String.IsNullOrEmpty(s))
        {

            **THIS GO IN STACK OVERFLOW**
            res = p.ItemOrder.ToString().PadLeft(5, pad) + "." + s;

        }
        else
            res = p.ItemOrder.ToString().PadLeft(5, pad);

        _pagina = p;

        if (_pagina.Parent == null)
            return res;
        while (_pagina.Parent != null)
        {
            res = CalculateStringOrder(_pagina.Parent, res);
        }
        //res = _stringOrder;
    }
    catch (StackOverflowException ex)
    { }
    return res;
}

我已经尝试卸载更新清除所有引用，但错误仍然存​​在。它一直有效。

@UPDATE

这是堆栈跟踪：

BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
BusinessLogic.dll!BusinessLogic.Page.CalculateStringOrder(BusinessLogic.Page p, string s) Riga 52   C#
>   BusinessLogic.dll!BusinessLogic.Page.StringOrder.get() Riga 29  C#
  BusinessLogic.dll!BusinessLogic.PageService.GetParentsTree.AnonymousMethod__2(BusinessLogic.Page x) Riga 40   C#
[Codice esterno]    
BusinessLogic.dll!BusinessLogic.PageService.GetParentsTree() Riga 40    C#
adico.dll!adico.Manager.Topics.Topics() Riga 21 C#
[Codice esterno]    

Answer 1

在Page.Parent.Parent.Parent.etc中，您有循环参考。

例如p.Parent = p; 或p.Parent.Parent.Parent = p;

这会在您指定的行上给出堆栈溢出异常，但它是来自调试器的红色鲱鱼。

var p = new Page { ItemOrder = "a" };
p.Parent = p;

Console.WriteLine(CalculateStringOrder(p, "xx"));

一种解决方案是记录您已处理的页面，例如：

var processed = new List<Page>();
...
if (processed.Contains(p)) return res;  // or throw an exception
processed.Add(p);

Answer 2

我假设此代码尝试从树的底部或路径开始收集ItemOrder个Page个对象的值，然后处理到root代码很麻烦但是如果有的话会失败路径中的任何圆圈，即路径A -> B -> C-> A将导致无限递归。当发生这种情况时，代码会尝试捕获不可避免的StackOverflowException并返回垃圾。

事实上，似乎有人试图混合使用递归和基于循环的代码来生成此路径。

如果生成路径的代码与生成字符串的代码分开，则更容易修复代码。以下代码将访问页面列表保存为@ freedomn-m建议：

private static Stack<Page> PathToTopRec(Page p, Stack<Page> visited=null )
{
    visited = visited ?? new Stack<Page>();
    if (visited.Contains(p))
        return visited;

    visited.Push(p);
    if (p.Parent == null)
        return visited;
    return PathToTopRec(p.Parent, visited);
}

此方法将按从root到leaf的顺序返回所有父页面。然后，您可以使用以下命令生成路径字符串：

    private static string CalculateStringOrder(Page p)
    {
        var path = PathToTopRec(p);

        var builder=new StringBuilder();
        foreach (var p in path)
        {
            builder.AppendFormat("{0:0000}.",p.ItemOrder);
        }
        builder.Remove(builder.Length- 1, 1);
        return builder.ToString();
    }

新方法将返回00001.00002.00003以获取以下数据：

    var p3 = new Page { ItemOrder = 3 };            
    var p2 = new Page { ItemOrder = 2 };
    var p1 = new Page { ItemOrder = 1 };
    p3.Parent = p2;
    p2.Parent = p1;
    var result=CalculateStringOrder(p3)

另一种选择是使用循环代替或递归：

    private static IEnumerable<Page> PathToTop(Page p)
    {
        var visited = new List<Page>();
        var current = p;
        while (current != null)
        {
            yield return current;
            visited.Add(current);
            current = !visited.Contains(current.Parent) 
                ? current.Parent 
                : null;
        }
    }

我使用迭代器，因此结果是IEnumerable，其页面与PathToTopRec相同。对字符串生成代码的唯一更改是更改添加对Reverse()的调用，因为迭代器将按照它们找到的顺序返回页面，从leaf到root。

var path = PathToTop(p).Reverse();

迭代器的优点是可以在其上应用任何LINQ运算符。实际上，字符串生成可能会改为：

var strings = PathToTop(p).Where(page=>page.ItemOrder>5)
                       .Select(page=>page.ItemOrder)
                       .Reverse()
                       .Select(it => string.Format("{0:0000}", it));
return String.Join(".", strings);

或LINQ运算符的任何其他组合。

原始代码混合了一个递归调用和一个while循环，这表明有人试图在某个时刻将递归代码转换为循环，但放弃了。