ASP.NET-使用 System.IO.File.Delete() 从 wwwroot 内的目录中删除文件？

Question

我有一个 ASP.NET SOAP Web 服务，其 Web 方法创建一个 PDF 文件，将其写入应用程序的“下载”目录，并将 URL 返回给用户。代码：

//Create the map images (MapPrinter) and insert them on the PDF (PagePrinter).
MemoryStream mstream = null;
FileStream fs = null;
try
{
    //Create the memorystream storing the pdf created.
    mstream = pgPrinter.GenerateMapImage();
    //Convert the memorystream to an array of bytes.
    byte[] byteArray = mstream.ToArray();
    //return byteArray;

    //Save PDF file to site's Download folder with a unique name.
    System.Text.StringBuilder sb = new System.Text.StringBuilder(Global.PhysicalDownloadPath);
    sb.Append("\\");
    string fileName = Guid.NewGuid().ToString() + ".pdf";
    sb.Append(fileName);
    string filePath = sb.ToString();
    fs = new FileStream(filePath, FileMode.CreateNew);
    fs.Write(byteArray, 0, byteArray.Length);
    string requestURI = this.Context.Request.Url.AbsoluteUri;
    string virtPath = requestURI.Remove(requestURI.IndexOf("Service.asmx")) + "Download/" + fileName;
    return virtPath;
}
catch (Exception ex)
{
    throw new Exception("An error has occurred creating the map pdf.", ex);
}
finally
{
    if (mstream != null) mstream.Close();
    if (fs != null) fs.Close();
    //Clean up resources
    if (pgPrinter != null) pgPrinter.Dispose();
}

然后在Web服务的Global.asax文件中，我在Application_Start事件监听器中设置了一个Timer。在计时器的 ElapsedEvent 侦听器中，我在下载目录中查找早于计时器间隔（对于测试 = 1 分钟，对于部署 ~20 分钟）的任何文件并将其删除。代码：

//Interval to check for old files (milliseconds), also set to delete files older than now minus this interval.
private static double deleteTimeInterval;
private static System.Timers.Timer timer;
//Physical path to Download folder.  Everything in this folder will be checked for deletion.
public static string PhysicalDownloadPath;

void Application_Start(object sender, EventArgs e)
{
    // Code that runs on application startup
    deleteTimeInterval = Convert.ToDouble(System.Configuration.ConfigurationManager.AppSettings["FileDeleteInterval"]);
    //Create timer with interval (milliseconds) whose elapse event will trigger the delete of old files
    //in the Download directory.
    timer = new System.Timers.Timer(deleteTimeInterval);
    timer.Enabled = true;
    timer.AutoReset = true;
    timer.Elapsed += new System.Timers.ElapsedEventHandler(OnTimedEvent);

    PhysicalDownloadPath = System.Web.Hosting.HostingEnvironment.ApplicationPhysicalPath + "Download";
}

private static void OnTimedEvent(object source, System.Timers.ElapsedEventArgs e)
{
    //Delete the files older than the time interval in the Download folder.
    var folder = new System.IO.DirectoryInfo(PhysicalDownloadPath);
    System.IO.FileInfo[] files = folder.GetFiles();
    foreach (var file in files)
    {
        if (file.CreationTime < DateTime.Now.AddMilliseconds(-deleteTimeInterval))
        {
            string path = PhysicalDownloadPath + "\\" + file.Name;
            System.IO.File.Delete(path);
        }
    }
}

除了一个例外，这工作得很好。当我将 Web 服务应用程序发布到 inetpub\wwwroot（Windows 7、IIS7）时，它不会删除下载目录中的旧文件。当我从 wwwroot 之外的物理目录发布到 IIS 时，该应用程序运行完美。显然，IIS 似乎对 Web 根目录中的文件设置了某种锁定。我已经测试过冒充管理员用户来运行该应用程序，但它仍然不起作用。有关如何在 wwwroot 中以编程方式规避锁定的任何提示？客户端可能希望将应用程序发布到根目录。

Answer 1

您的问题可能与以下事实有关：如果主文件夹中包含的目录或文件发生更改，IIS 会重新加载 Web 服务应用程序。

尝试在应用程序根文件夹之外的临时文件夹中创建/删除文件（请注意该文件夹的权限以允许 IIS 读取/写入文件）。

Answer 2

为什么不使用隔离存储，而不是直接写入文件系统？
http://msdn.microsoft.com/en- us/library/system.io.isolatedstorage.isolatedstorage.aspx

这应该可以解决您遇到的任何基于位置或权限的问题

Answer 3

我忘了回来回答我的问题。

我必须向 IIS_IUSRS 组授予我读取/写入文件的目录的修改权限。

感谢所有回答的人。