如何从C＃获取虚拟驱动器中文件的物理路径

Question

The problem is posed in the following way:

I create a virtual drive or "virtual drive letter" with a command in DOS called subst by means of a bat like this:

@echo off
cd \
subst J: /D
subst J: C:\Virtual_Disk\Unit_J

In the list of windows units I see the unit created,in which I placed some files and an executable. I am currently developing a program in c # where it calls the path of the executable that is in the virtual path, and suddenly, an exception is thrown that indicates that the path of the executable is not found even though the executable is there, I look at the properties of the executable. executable and in the field location indicates the virtual path of that executable but not the physical route. If I was not clear, I will give an example:

(1) virtual path of the executable

J:\Program\executable.exe

(2) physical route where the executable is located

C:\Virtual_Disks\Unit_J\Program\executable.exe

C# captures the virtual path of the executable (1) but not where it really is (2).

Not being more, I appreciate the help provided.

Answer 1

This should work, from here :

    [DllImport("kernel32.dll")]
    private static extern uint QueryDosDevice(string lpDeviceName, StringBuilder lpTargetPath, int ucchMax);

    private static string GetPhysicalPath(string path)
    {
        if (string.IsNullOrEmpty(path))
        {
            throw new ArgumentNullException("path");
        }

        // Get the drive letter
        var pathRoot = Path.GetPathRoot(path);
        if (string.IsNullOrEmpty(pathRoot))
        {
            throw new ArgumentNullException("path");
        }

        var substPrefix = @"\??\";
        var lpDeviceName = pathRoot.Replace(@"\", string.Empty);            
        var lpTargetPath = new StringBuilder(260);
        if (QueryDosDevice(lpDeviceName, lpTargetPath, lpTargetPath.Capacity) != 0)
        {
            string result;

            // If drive is substed, the result will be in the format of "\??\C:\RealPath\".
            if (lpTargetPath.ToString().StartsWith(substPrefix))
            {
                // Strip the \??\ prefix.
                var root = lpTargetPath.ToString().Remove(0, substPrefix.Length);
                result = Path.Combine(root, path.Replace(Path.GetPathRoot(path), string.Empty));
            }

            else
            {
                // if not SUBSTed, just assume it's not mapped.
                result = path;
            }

            return result;
        }
        else
        {
            return null;
        }
    }