GetFileSystemInfosで短いパスを長いパスに変換する方法

GetFileSystemInfosで短いパスを長いパスに変換する方法
VB.NET

Public Shared Function GetLongPath(ByVal path As String) As String
    Dim root As String = System.IO.Path.GetPathRoot(path)
    Dim folders As String() = path.Substring(root.Length). _
        Split(System.IO.Path.DirectorySeparatorChar)

    Dim res As String = root
    Dim name As String
    For Each name In folders
        Dim di = New DirectoryInfo(res)
        Dim fsi As System.IO.FileSystemInfo() = _
            di.GetFileSystemInfos(name)
        If fsi.Length = 1 Then
            res = fsi(0).FullName
        Else
            Throw New Exception("ERROR")
        End If
    Next name

    Return res
End Function

C#

public static string GetLongPath(string path)
{
    string root = System.IO.Path.GetPathRoot(path);
    string[] folders = path.Substring(root.Length)
        .Split(System.IO.Path.DirectorySeparatorChar);

    string res = root;
    foreach (string name in folders)
    {
        System.IO.DirectoryInfo di = new DirectoryInfo(res);
        System.IO.FileSystemInfo[] fsi = di.GetFileSystemInfos(name);
        if (fsi.Length == 1)
            res = fsi[0].FullName;
        else
            throw new Exception("ERROR");
    }

    return res;
}