Vista 中使用 .Net 2.0 进行频繁文件 I/O 时出现 UnauthorizedAccessException

发布于 2024-07-18 08:15:33 字数 1544 浏览 7 评论 0原文

在工作中，我们已经从 Windows XP 迁移到 Windows Vista。迁移后，我的一些使用 nUnit 的单元测试开始随机失败，并抛出 System.UnauthorizedAccessException。每个失败的测试都涉及将作为嵌入资源存储在测试 DLL 中的测试所用的文件写入到当前目录，运行测试，然后删除它们，通常是在安装/拆卸或夹具安装/拆卸中快速连续地进行。我这样做是为了让我的测试与运行它们的每个开发人员驱动器上的位置无关，而不用担心相对文件路径。

在排查此问题时，我发现它与文件的创建和删除有关。删除时，每次删除都遵循以下模式：

if( File.Exists(path) ) { File.Delete(path) }

当我用 try-catch 块和 catch 上的断点包围它时（如果引发异常），该文件已经从磁盘中删除。对于文件创建失败，通常使用XmlWriter或StreamWriter，分别指定覆盖文件（如果存在）。

奇怪的是，在调查过程中，我创建了这个 C# 程序，它似乎重新创建了异常：

class Program
{
    static void Main(string[] args)
    {
        int i = 0;
        try
        {              
            while (true)
            {
                System.IO.TextWriter writer = new System.IO.StreamWriter("file.txt");
                i++;
                System.Console.Out.WriteLine(i);
                writer.Write(i);
                writer.Close();
                System.IO.File.Delete("file.txt");
            }
        }
        catch (System.UnauthorizedAccessException ex)
        {
            System.Console.Out.WriteLine("Boom at: " + i.ToString());
        }

    }
}

在我们的一台仍然装有 XP 的机器上，它将不断迭代到数十万次，而不会出现异常，直到我杀死它。在我们的任何 Vista 机器上，它都会在 150 到 500 次迭代之间打印“Boom”。

由于我在工作之外无法访问 Vista 计算机，因此我无法确定这个特殊的“怪癖”是否是由于我的雇主对 Vista 的安全配置或 Vista 本身造成的。

可以说，我很困惑。

编辑：

我要感谢大家的回复。我使用 Christian 建议的进程监视器，发现 Windows Vista SearchIndexer 和 TortoiseSVN 的 TSVNCache 进程在我的代码运行时尝试访问目标文件，正如 Martin 建议的那样。

再次感谢。

原文

At work, we have migrated from Windows XP to Windows Vista. After the migration, some of my unit tests, using nUnit, started to randomly fail with the System.UnauthorizedAccessException being thrown. The failing tests each involve writing files used for tests stored as embedded resources in the test DLL to the current directory, running the tests, then deleting them, typically in the setup/teardown or the fixture setup/teardown, in rapid succession. I do this so that my tests are agnostic to the location on each developer's drive that they are ran from and not worrying about relative file paths.

While troubleshooting this, I found that it related to the creation and deletion of the files. On deletion, each delete follows the pattern:

if( File.Exists(path) ) { File.Delete(path) }

When I surround this with a try-catch block and breakpoint on the catch (if the exception was thrown), the file would already be deleted from the disk. For the failures of file creation, usually using XmlWriter or StreamWriter, each are specified to overwrite the file if it exists.

Odd thing is, while investigating, I created this C# program that seems to recreate the exception:

class Program
{
    static void Main(string[] args)
    {
        int i = 0;
        try
        {              
            while (true)
            {
                System.IO.TextWriter writer = new System.IO.StreamWriter("file.txt");
                i++;
                System.Console.Out.WriteLine(i);
                writer.Write(i);
                writer.Close();
                System.IO.File.Delete("file.txt");
            }
        }
        catch (System.UnauthorizedAccessException ex)
        {
            System.Console.Out.WriteLine("Boom at: " + i.ToString());
        }

    }
}

On one of our machines that still has XP on it, it will keep iterating into the hundreds of thousands without excepting until I kill it. On any of our Vista machines, it will print "Boom" anywhere between 150 and 500 iterations.

Since I do not have access to a Vista machine outside of work, I can't determine whether this particular 'quirk' is because of my employer's security configuration of Vista or Vista itself.

Suffice to say, I am quite stumped.

EDIT:

I would like to thank everyone for their responses. I used the Process Monitor suggested by Christian and found that the Windows Vista SearchIndexer and TortoiseSVN's TSVNCache processes were trying to access the target file while my code was running, as suggested by Martin.

Thanks again.

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