How to obtain the target of a symbolic link (or Reparse Point) using .Net?

In .NET, I think I can determine if a file is a symbolic link by calling System.IO.File.GetAttributes(), and checking for the ReparsePoint bit. like so:

var a = System.IO.File.GetAttributes(fileName);
if ((a & FileAttributes.ReparsePoint) != 0)
{
    // it's a symlink
}

How can I obtain the target of the symbolic link, in this case?

ps: I know how to create a symbolic link. It requires P/Invoke:

[Interop.DllImport("kernel32.dll", EntryPoint="CreateSymbolicLinkW", CharSet=Interop.CharSet.Unicode)] 
public static extern int CreateSymbolicLink(string lpSymlinkFileName, string lpTargetFileName, int dwFlags); 

Based on the answer that mentioned GetFinalPathNameByHandle here is the C# code that does this (since all other answers were just pointers):

Usage

var path = NativeMethods.GetFinalPathName(@"c:\link");

Code:

public static class NativeMethods
{
    private static readonly IntPtr INVALID_HANDLE_VALUE = new IntPtr(-1);

    private const uint FILE_READ_EA = 0x0008;
    private const uint FILE_FLAG_BACKUP_SEMANTICS = 0x2000000;

    [DllImport("Kernel32.dll", SetLastError = true, CharSet = CharSet.Auto)]
    static extern uint GetFinalPathNameByHandle(IntPtr hFile, [MarshalAs(UnmanagedType.LPTStr)] StringBuilder lpszFilePath, uint cchFilePath, uint dwFlags);

    [DllImport("kernel32.dll", SetLastError = true)]
    [return: MarshalAs(UnmanagedType.Bool)]
    static extern bool CloseHandle(IntPtr hObject);

    [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    public static extern IntPtr CreateFile(
            [MarshalAs(UnmanagedType.LPTStr)] string filename,
            [MarshalAs(UnmanagedType.U4)] uint access,
            [MarshalAs(UnmanagedType.U4)] FileShare share,
            IntPtr securityAttributes, // optional SECURITY_ATTRIBUTES struct or IntPtr.Zero
            [MarshalAs(UnmanagedType.U4)] FileMode creationDisposition,
            [MarshalAs(UnmanagedType.U4)] uint flagsAndAttributes,
            IntPtr templateFile);

    public static string GetFinalPathName(string path)
    {
        var h = CreateFile(path, 
            FILE_READ_EA, 
            FileShare.ReadWrite | FileShare.Delete, 
            IntPtr.Zero, 
            FileMode.Open, 
            FILE_FLAG_BACKUP_SEMANTICS,
            IntPtr.Zero);
        if (h == INVALID_HANDLE_VALUE)
            throw new Win32Exception();

        try
        {
            var sb = new StringBuilder(1024);
            var res = GetFinalPathNameByHandle(h, sb, 1024, 0);
            if (res == 0)
                throw new Win32Exception();

            return sb.ToString();
        }
        finally
        {
            CloseHandle(h);
        }
    }
}

You have to use DeviceIoControl() and send the FSCTL_GET_REPARSE_POINT control code. The P/Invoke and API usage details are quite gritty, but it Googles really well.

Open the file using CreateFile, and then pass the handle to GetFinalPathNameByHandle.

In .NET 6 you can use the property LinkTarget

bool IsLink(string path)
{
    var fi = new FileInfo(path);
    return fi.LinkTarget != null
}