我的应用程序对任何文件夹都没有权限

Question

我在 VS2015 中创建了一个 UWP 应用程序并将其部署到我的 windows 10 物联网设备 (RPI 3)。

已部署到此文件夹：

C:\Data\Users\DefaultAccount\AppData\Local\DevelopmentFiles\

现在运行时，它没有文件访问权限。我尝试在 its own directory 中写入，从 c:\data 中读取，从 c:\mydir 中读取（新创建的，赋予每个用户完全访问权限）但没有读取（或写入）的权限.

奇怪的是，所有用于查看我的应用程序在哪个帐户下的代码示例运行不适用于物联网应用程序。

Answer 1

I've tried to write in its own directory

The app's install directory is a read-only location.

to read from c:\data, to read from c:\mydir (newly created, given every user full access rights) but no rights to read (or write).

Not all folders on your device are accesible by Universal Windows Apps. To make a folder accesible to a UWP app, you can use FolderPermissions tool. For example run FolderPermissions c:\test -e to give UWP apps access to c:\test folder. Note this will work only with native Win32 apis for eg. CreateFile2 and not with WinRT apis like StorageFolder, StorageFile etc.

要使用 Win32 api ReadFile，您需要使用 PInvoke。代码如下：

    /*Part1: preparation for using Win32 apis*/
    const uint GENERIC_READ = 0x80000000;
    const uint OPEN_EXISTING = 3;
    System.IntPtr handle;

    [System.Runtime.InteropServices.DllImport("kernel32", SetLastError = true, ThrowOnUnmappableChar = true, CharSet = System.Runtime.InteropServices.CharSet.Unicode)]
    static extern unsafe System.IntPtr CreateFile
    (
        string FileName,          // file name
        uint DesiredAccess,       // access mode
        uint ShareMode,           // share mode
        uint SecurityAttributes,  // Security Attributes
        uint CreationDisposition, // how to create
        uint FlagsAndAttributes,  // file attributes
        int hTemplateFile         // handle to template file
    );

    [System.Runtime.InteropServices.DllImport("kernel32", SetLastError = true)]
    static extern unsafe bool ReadFile
    (
        System.IntPtr hFile,      // handle to file
        void* pBuffer,            // data buffer
        int NumberOfBytesToRead,  // number of bytes to read
        int* pNumberOfBytesRead,  // number of bytes read
        int Overlapped            // overlapped buffer
    );

    [System.Runtime.InteropServices.DllImport("kernel32", SetLastError = true)]
    static extern unsafe bool CloseHandle
    (
        System.IntPtr hObject // handle to object
    );

    public bool Open(string FileName)
    {
        // open the existing file for reading       
        handle = CreateFile
        (
            FileName,
            GENERIC_READ,
            0,
            0,
            OPEN_EXISTING,
            0,
            0
        );

        if (handle != System.IntPtr.Zero)
        {
            return true;
        }
        else
        {
            return false;
        }
    }
    public unsafe int Read(byte[] buffer, int index, int count)
    {
        int n = 0;
        fixed (byte* p = buffer)
        {
            if (!ReadFile(handle, p + index, count, &n, 0))
            {
                return 0;
            }
        }
        return n;
    }

    public bool Close()
    {
        return CloseHandle(handle);
    }
    /*End Part1*/

    /*Part2: Test reading */
    private void ReadFile()
    {
        string curFile = @"c:\test\mytest.txt";

        byte[] buffer = new byte[128];


        if (Open(curFile))
        {
            // Assume that an ASCII file is being read.
            System.Text.ASCIIEncoding Encoding = new System.Text.ASCIIEncoding();

            int bytesRead;
            do
            {
                bytesRead = Read(buffer, 0, buffer.Length);
                string content = Encoding.GetString(buffer, 0, bytesRead);
                System.Diagnostics.Debug.WriteLine("{0}", content);
            }
            while (bytesRead > 0);

            Close();
        }
        else
        {
            System.Diagnostics.Debug.WriteLine("Failed to open requested file");
        }

    }
    /*End Part2*/

注意：这里有一些 不安全 代码可能不会发布到商店。但是如果你只是在 Windows IoT core 上使用它就不会打扰你。

我的应用程序对任何文件夹都没有权限

My application has no rights on any folder

windows-10-iot-core

uwp