我正在尝试使用 Shell32 在 C# 中获取扩展文件属性。

我的代码如下。

        var file = FileUpload1.PostedFile;

        List<string> arrHeaders = new List<string>();

        Shell shell = new ShellClass();

        //Exception is thrown at next line
        Folder rFolder = shell.NameSpace(Path.GetDirectoryName(file.FileName));
        FolderItem rFiles = rFolder.ParseName(Path.GetFileName(file.FileName));

        for (int i = 0; i < short.MaxValue; i++)
        {
            string value = rFolder.GetDetailsOf(rFiles, i).Trim();
            arrHeaders.Add(value);
        }

我收到如下异常。

消息 - 无法将类型为“Shell32.ShellClass”的 COM 对象转换为接口(interface)类型“Shell32.IShellDispatch6”。此操作失败，因为 IID 为“{286E6F1B-7113-4355-9562-96B7E9D64C54}”的接口(interface)的 COM 组件上的 QueryInterface 调用因以下错误而失败:不支持此类接口(interface)(HRESULT 异常:0x80004002 (E_NOINTERFACE)) .

堆栈跟踪 - 在 System.StubHelpers.StubHelpers.GetCOMIPFromRCW(Object objSrc、IntPtr pCPCMD、IntPtr& ppTarget、Boolean& pfNeedsRelease) 在 Shell32.ShellClass.NameSpace(对象 vDir) 在 C:\Projects\PBSWebApplication\PBSWebApplication\PBSWebApplication\Test.aspx.cs:line 33 中的 PBSWebApplication.Test.Button1_OnClick(Object sender, EventArgs e) 在 System.Web.UI.WebControls.Button.OnClick(EventArgs e) 在 System.Web.UI.WebControls.Button.RaisePostBackEvent(字符串事件参数) 在 System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(字符串事件参数) 在 System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl，String eventArgument) 在 System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) 在 System.Web.UI.Page.ProcessRequestMain( bool 值 includeStagesBeforeAsyncPoint， bool 值 includeStagesAfterAsyncPoint)

如何解决这个问题？

谢谢。

最佳答案

如您所见，这是因为 Shell32 需要 STA 线程。如果您不能像在您的解决方案中那样简单地将您的应用程序配置为使用 STA 线程运行，那么作为替代方案，您可以创建一个单独的 STA 线程，使用它来运行 Shell32 代码，然后继续执行。例如this这是我在编写 SSIS 脚本任务时得到的结果，据我所知，它总是在 MTA 线程上运行。在我的例子中，我正在调用 Shell32 (CopyHere) 的不同方法，但相同的逻辑将适用于您要调用的任何方法:

    /// <summary>
    /// Ugh! SSIS runs script tasks on MTA threads but Shell32 only wants to 
    /// run on STA thread. So start a new STA thread to call UnZip, block 
    /// till it's done, then return. 
    /// We use Shell32 since .net 2 doesn't have ZipFile and we prefer not to 
    /// ship other dlls as they normally need to be deployed to the GAC. So this 
    /// is easiest, although not very pretty.
    /// </summary>
    /// <param name="zipFile">File to unzip</param>
    /// <param name="folderPath">Folder to put the unzipped files</param>
    public static void UnZipFromMTAThread(string zipFile, string folderPath)
    {
        object[] args = new object[] { zipFile, folderPath };
        if (Thread.CurrentThread.GetApartmentState() == ApartmentState.STA)
        {
            UnZip(args);
        }
        else
        {
            Thread staThread = new Thread(new ParameterizedThreadStart(UnZip));
            staThread.SetApartmentState(ApartmentState.STA);
            staThread.Start(args);
            staThread.Join();
        }
    }

    /// <summary>
    /// From http://www.fluxbytes.com/csharp/unzipping-files-using-shell32-in-c/ but with 
    /// args packed in object array so can be called from new STA Thread in UnZipFromMTAThread().
    /// </summary>
    /// <param name="param">object array containing: [string zipFile, string destinationFolderPath]</param>
    private static void UnZip(object param)
    {
        object[] args = (object[]) param;
        string zipFile = (string)args[0];
        string folderPath = (string)args[1];


        if (!File.Exists(zipFile))
            throw new FileNotFoundException();

        if (!Directory.Exists(folderPath))
            Directory.CreateDirectory(folderPath);

        Shell32.Shell objShell = new Shell32.Shell();
        Shell32.Folder destinationFolder = objShell.NameSpace(folderPath);
        Shell32.Folder sourceFile = objShell.NameSpace(zipFile);

        foreach (var file in sourceFile.Items())
        {
            // Flags are: No progress displayed, Respond with 'Yes to All' for any dialog, no UI on error
            // I added 1024 although not sure it's relevant with Zip files. 
            // See https://msdn.microsoft.com/en-us/library/windows/desktop/bb787866%28v=vs.85%29.aspx?f=255&MSPPError=-2147217396
            destinationFolder.CopyHere(file, 4 | 16 | 1024); 
        }
    }

关于c# - 使用 Shell32 获取文件扩展属性时出现异常，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/31403956/