Get free disk space

Question

Given each of the inputs below, I\'d like to get free space on that location. Something like

long GetFreeSpace(string path)

Inputs:

Answer 1

Here is a refactored and simplified version of the @sasha_gud answer:

    [DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
    [return: MarshalAs(UnmanagedType.Bool)]
    public static extern bool GetDiskFreeSpaceEx(string lpDirectoryName,
        out ulong lpFreeBytesAvailable,
        out ulong lpTotalNumberOfBytes,
        out ulong lpTotalNumberOfFreeBytes);

    public static ulong GetDiskFreeSpace(string path)
    {
        if (string.IsNullOrEmpty(path))
        {
            throw new ArgumentNullException("path");
        }

        ulong dummy = 0;

        if (!GetDiskFreeSpaceEx(path, out ulong freeSpace, out dummy, out dummy))
        {
            throw new Win32Exception(Marshal.GetLastWin32Error());
        }

        return freeSpace;
    }